diff --git a/td/telegram/MessageEntity.cpp b/td/telegram/MessageEntity.cpp
index eafd2294..b4724871 100644
--- a/td/telegram/MessageEntity.cpp
+++ b/td/telegram/MessageEntity.cpp
@@ -1146,13 +1146,36 @@ static void check_non_intersecting(const vector<MessageEntity> &entities) {
   }
 }
 
-static int32 get_entity_type_mask(MessageEntity::Type type) {
+static constexpr int32 get_entity_type_mask(MessageEntity::Type type) {
   return 1 << static_cast<int32>(type);
 }
 
+static constexpr int32 get_splittable_entities_mask() {
+  return get_entity_type_mask(MessageEntity::Type::Bold) | get_entity_type_mask(MessageEntity::Type::Italic) |
+         get_entity_type_mask(MessageEntity::Type::Underline) |
+         get_entity_type_mask(MessageEntity::Type::Strikethrough);
+}
+
+static constexpr int32 get_blockquote_entities_mask() {
+  return get_entity_type_mask(MessageEntity::Type::BlockQuote);
+}
+
+static constexpr int32 get_continuous_entities_mask() {
+  return get_entity_type_mask(MessageEntity::Type::Mention) | get_entity_type_mask(MessageEntity::Type::Hashtag) |
+         get_entity_type_mask(MessageEntity::Type::BotCommand) | get_entity_type_mask(MessageEntity::Type::Url) |
+         get_entity_type_mask(MessageEntity::Type::EmailAddress) | get_entity_type_mask(MessageEntity::Type::TextUrl) |
+         get_entity_type_mask(MessageEntity::Type::MentionName) | get_entity_type_mask(MessageEntity::Type::Cashtag) |
+         get_entity_type_mask(MessageEntity::Type::PhoneNumber) |
+         get_entity_type_mask(MessageEntity::Type::BankCardNumber);
+}
+
+static constexpr int32 get_pre_entities_mask() {
+  return get_entity_type_mask(MessageEntity::Type::Pre) | get_entity_type_mask(MessageEntity::Type::Code) |
+         get_entity_type_mask(MessageEntity::Type::PreCode);
+}
+
 static int32 is_splittable_entity(MessageEntity::Type type) {
-  return type == MessageEntity::Type::Bold || type == MessageEntity::Type::Italic ||
-         type == MessageEntity::Type::Underline || type == MessageEntity::Type::Strikethrough;
+  return (get_entity_type_mask(type) & get_splittable_entities_mask()) != 0;
 }
 
 static int32 is_blockquote_entity(MessageEntity::Type type) {
@@ -1160,15 +1183,11 @@ static int32 is_blockquote_entity(MessageEntity::Type type) {
 }
 
 static int32 is_continuous_entity(MessageEntity::Type type) {
-  return type == MessageEntity::Type::Mention || type == MessageEntity::Type::Hashtag ||
-         type == MessageEntity::Type::BotCommand || type == MessageEntity::Type::Url ||
-         type == MessageEntity::Type::EmailAddress || type == MessageEntity::Type::TextUrl ||
-         type == MessageEntity::Type::MentionName || type == MessageEntity::Type::Cashtag ||
-         type == MessageEntity::Type::PhoneNumber || type == MessageEntity::Type::BankCardNumber;
+  return (get_entity_type_mask(type) & get_continuous_entities_mask()) != 0;
 }
 
 static int32 is_pre_entity(MessageEntity::Type type) {
-  return type == MessageEntity::Type::Pre || type == MessageEntity::Type::Code || type == MessageEntity::Type::PreCode;
+  return (get_entity_type_mask(type) & get_pre_entities_mask()) != 0;
 }
 
 static constexpr size_t SPLITTABLE_ENTITY_TYPE_COUNT = 4;
@@ -1215,9 +1234,14 @@ static bool are_entities_valid(const vector<MessageEntity> &entities) {
         // Pre and Code can't contain nested entities
         return false;
       }
-      if (is_continuous_entity(parent_type) &&
-          (is_pre_entity(entity.type) || is_continuous_entity(entity.type) || is_blockquote_entity(entity.type))) {
-        // continuous can't contain other continuous and blockquote
+      // parents are not pre after this point
+      if (is_pre_entity(entity.type) && (nested_entity_type_mask & ~get_blockquote_entities_mask()) != 0) {
+        // Pre and Code can't be contained in other entities, except blockquote
+        return false;
+      }
+      if ((is_continuous_entity(entity.type) || is_blockquote_entity(entity.type)) &&
+          (nested_entity_type_mask & get_continuous_entities_mask()) != 0) {
+        // continuous and blockquote can't be contained in continuous
         return false;
       }
     }
@@ -1225,7 +1249,7 @@ static bool are_entities_valid(const vector<MessageEntity> &entities) {
     if (is_splittable_entity(entity.type)) {
       auto index = get_splittable_entity_type_index(entity.type);
       if (end_pos[index] >= entity.offset) {
-        // the entities may be need to merged
+        // the entities can be merged
         return false;
       }
       end_pos[index] = entity.offset + entity.length;
@@ -2788,11 +2812,11 @@ void split_entities(vector<MessageEntity> &entities, const vector<MessageEntity>
         auto index = get_splittable_entity_type_index(type);
         if (end_pos[index] != 0 && begin_pos[index] < offset) {
           if (end_pos[index] <= offset) {
-            result.emplace_back(type, begin_pos[index], end_pos[index]);
+            result.emplace_back(type, begin_pos[index], end_pos[index] - begin_pos[index]);
             begin_pos[index] = 0;
             end_pos[index] = 0;
           } else {
-            result.emplace_back(type, begin_pos[index], offset);
+            result.emplace_back(type, begin_pos[index], offset - begin_pos[index]);
             begin_pos[index] = offset;
           }
         }
@@ -2826,7 +2850,7 @@ void split_entities(vector<MessageEntity> &entities, const vector<MessageEntity>
       result.resize(old_size);
     }
   }
-  add_entities(std::numeric_limits<size_t>::max());
+  add_entities(std::numeric_limits<int32>::max());
   entities = std::move(result);
   // entities are sorted only by offset now, re-sort if needed
   if (!std::is_sorted(entities.begin(), entities.end())) {
diff --git a/test/message_entities.cpp b/test/message_entities.cpp
index bba2bcec..548cfab3 100644
--- a/test/message_entities.cpp
+++ b/test/message_entities.cpp
@@ -575,8 +575,9 @@ TEST(MessageEntities, url) {
 
 static void check_fix_formatted_text(td::string str, td::vector<td::MessageEntity> entities,
                                      const td::string &expected_str,
-                                     const td::vector<td::MessageEntity> &expected_entities, bool allow_empty,
-                                     bool skip_new_entities, bool skip_bot_commands, bool for_draft) {
+                                     const td::vector<td::MessageEntity> &expected_entities, bool allow_empty = true,
+                                     bool skip_new_entities = false, bool skip_bot_commands = false,
+                                     bool for_draft = true) {
   ASSERT_TRUE(
       td::fix_formatted_text(str, entities, allow_empty, skip_new_entities, skip_bot_commands, for_draft).is_ok());
   ASSERT_STREQ(expected_str, str);
@@ -780,6 +781,104 @@ TEST(MessageEntities, fix_formatted_text) {
       check_fix_formatted_text(text, {{type, 0, 1, "http://telegram.org/"}}, "", {}, true, false, false, true);
     }
   }
+
+  check_fix_formatted_text("abc", {{td::MessageEntity::Type::Italic, 1, 1}, {td::MessageEntity::Type::Italic, 0, 1}},
+                           "abc", {{td::MessageEntity::Type::Italic, 0, 2}});
+  check_fix_formatted_text("abc", {{td::MessageEntity::Type::Italic, 1, 1}, {td::MessageEntity::Type::Italic, 1, 1}},
+                           "abc", {{td::MessageEntity::Type::Italic, 1, 1}});
+  check_fix_formatted_text("abc", {{td::MessageEntity::Type::Italic, 0, 2}, {td::MessageEntity::Type::Italic, 1, 2}},
+                           "abc", {{td::MessageEntity::Type::Italic, 0, 3}});
+  check_fix_formatted_text("abc", {{td::MessageEntity::Type::Italic, 0, 2}, {td::MessageEntity::Type::Italic, 2, 1}},
+                           "abc", {{td::MessageEntity::Type::Italic, 0, 3}});
+  check_fix_formatted_text("abc", {{td::MessageEntity::Type::Italic, 0, 1}, {td::MessageEntity::Type::Italic, 2, 1}},
+                           "abc", {{td::MessageEntity::Type::Italic, 0, 1}, {td::MessageEntity::Type::Italic, 2, 1}});
+  check_fix_formatted_text("abc", {{td::MessageEntity::Type::Italic, 0, 2}, {td::MessageEntity::Type::Bold, 1, 2}},
+                           "abc",
+                           {{td::MessageEntity::Type::Italic, 0, 1},
+                            {td::MessageEntity::Type::Bold, 1, 2},
+                            {td::MessageEntity::Type::Italic, 1, 1}});
+  check_fix_formatted_text("abc", {{td::MessageEntity::Type::Italic, 0, 2}, {td::MessageEntity::Type::Bold, 2, 1}},
+                           "abc", {{td::MessageEntity::Type::Italic, 0, 2}, {td::MessageEntity::Type::Bold, 2, 1}});
+  check_fix_formatted_text("abc", {{td::MessageEntity::Type::Italic, 0, 1}, {td::MessageEntity::Type::Bold, 2, 1}},
+                           "abc", {{td::MessageEntity::Type::Italic, 0, 1}, {td::MessageEntity::Type::Bold, 2, 1}});
+
+  // _a*b*_
+  check_fix_formatted_text(
+      "ab", {{td::MessageEntity::Type::Underline, 0, 2}, {td::MessageEntity::Type::Strikethrough, 1, 1}}, "ab",
+      {{td::MessageEntity::Type::Underline, 0, 2}, {td::MessageEntity::Type::Strikethrough, 1, 1}});
+  check_fix_formatted_text("ab",
+                           {{td::MessageEntity::Type::Underline, 0, 1},
+                            {td::MessageEntity::Type::Underline, 1, 1},
+                            {td::MessageEntity::Type::Strikethrough, 1, 1}},
+                           "ab",
+                           {{td::MessageEntity::Type::Underline, 0, 1},
+                            {td::MessageEntity::Type::Underline, 1, 1},
+                            {td::MessageEntity::Type::Strikethrough, 1, 1}});
+  check_fix_formatted_text(
+      "ab", {{td::MessageEntity::Type::Strikethrough, 0, 2}, {td::MessageEntity::Type::Underline, 1, 1}}, "ab",
+      {{td::MessageEntity::Type::Strikethrough, 0, 2}, {td::MessageEntity::Type::Underline, 1, 1}});
+  check_fix_formatted_text("ab",
+                           {{td::MessageEntity::Type::Strikethrough, 0, 1},
+                            {td::MessageEntity::Type::Strikethrough, 1, 1},
+                            {td::MessageEntity::Type::Underline, 1, 1}},
+                           "ab",
+                           {{td::MessageEntity::Type::Strikethrough, 0, 1},
+                            {td::MessageEntity::Type::Underline, 1, 1},
+                            {td::MessageEntity::Type::Strikethrough, 1, 1}});
+
+  // _*a*b_
+  check_fix_formatted_text(
+      "ab", {{td::MessageEntity::Type::Underline, 0, 2}, {td::MessageEntity::Type::Strikethrough, 0, 1}}, "ab",
+      {{td::MessageEntity::Type::Underline, 0, 2}, {td::MessageEntity::Type::Strikethrough, 0, 1}});
+  check_fix_formatted_text(
+      "ab",
+      {{td::MessageEntity::Type::Underline, 0, 1},
+       {td::MessageEntity::Type::Underline, 1, 1},
+       {td::MessageEntity::Type::Strikethrough, 0, 1}},
+      "ab", {{td::MessageEntity::Type::Underline, 0, 2}, {td::MessageEntity::Type::Strikethrough, 0, 1}});
+
+  // _*a*_\r_*b*_
+  check_fix_formatted_text("a\rb",
+                           {{td::MessageEntity::Type::Bold, 0, 1},
+                            {td::MessageEntity::Type::Strikethrough, 0, 1},
+                            {td::MessageEntity::Type::Bold, 2, 1},
+                            {td::MessageEntity::Type::Strikethrough, 2, 1}},
+                           "ab",
+                           {{td::MessageEntity::Type::Bold, 0, 2}, {td::MessageEntity::Type::Strikethrough, 0, 2}});
+  check_fix_formatted_text("a\nb",
+                           {{td::MessageEntity::Type::Bold, 0, 1},
+                            {td::MessageEntity::Type::Strikethrough, 0, 1},
+                            {td::MessageEntity::Type::Bold, 2, 1},
+                            {td::MessageEntity::Type::Strikethrough, 2, 1}},
+                           "a\nb",
+                           {{td::MessageEntity::Type::Bold, 0, 1},
+                            {td::MessageEntity::Type::Strikethrough, 0, 1},
+                            {td::MessageEntity::Type::Bold, 2, 1},
+                            {td::MessageEntity::Type::Strikethrough, 2, 1}});
+
+  // _`a`_
+  check_fix_formatted_text("a", {{td::MessageEntity::Type::Pre, 0, 1}, {td::MessageEntity::Type::Strikethrough, 0, 1}},
+                           "a", {{td::MessageEntity::Type::Pre, 0, 1}});
+  check_fix_formatted_text("a", {{td::MessageEntity::Type::Strikethrough, 0, 1}, {td::MessageEntity::Type::Pre, 0, 1}},
+                           "a", {{td::MessageEntity::Type::Pre, 0, 1}});
+  check_fix_formatted_text("abc",
+                           {{td::MessageEntity::Type::Pre, 0, 3}, {td::MessageEntity::Type::Strikethrough, 1, 1}},
+                           "abc", {{td::MessageEntity::Type::Pre, 0, 3}});
+  check_fix_formatted_text(
+      "abc", {{td::MessageEntity::Type::Pre, 1, 1}, {td::MessageEntity::Type::Strikethrough, 0, 3}}, "abc",
+      {{td::MessageEntity::Type::Strikethrough, 0, 1},
+       {td::MessageEntity::Type::Pre, 1, 1},
+       {td::MessageEntity::Type::Strikethrough, 2, 1}});
+  check_fix_formatted_text(
+      "abc", {{td::MessageEntity::Type::Pre, 1, 1}, {td::MessageEntity::Type::Strikethrough, 1, 2}}, "abc",
+      {{td::MessageEntity::Type::Pre, 1, 1}, {td::MessageEntity::Type::Strikethrough, 2, 1}});
+  check_fix_formatted_text(
+      "abc", {{td::MessageEntity::Type::Pre, 1, 1}, {td::MessageEntity::Type::Strikethrough, 0, 2}}, "abc",
+      {{td::MessageEntity::Type::Strikethrough, 0, 1}, {td::MessageEntity::Type::Pre, 1, 1}});
+  check_fix_formatted_text("abc", {{td::MessageEntity::Type::Pre, 0, 3}, {td::MessageEntity::Type::BlockQuote, 1, 1}},
+                           "abc", {{td::MessageEntity::Type::BlockQuote, 1, 1}});
+  check_fix_formatted_text("abc", {{td::MessageEntity::Type::BlockQuote, 0, 3}, {td::MessageEntity::Type::Pre, 1, 1}},
+                           "abc", {{td::MessageEntity::Type::BlockQuote, 0, 3}, {td::MessageEntity::Type::Pre, 1, 1}});
 }
 
 static void check_parse_html(td::string text, const td::string &result, const td::vector<td::MessageEntity> &entities) {