diff --git a/td/telegram/SpecialStickerSetType.cpp b/td/telegram/SpecialStickerSetType.cpp
index 42ffbc50a..2804127ea 100644
--- a/td/telegram/SpecialStickerSetType.cpp
+++ b/td/telegram/SpecialStickerSetType.cpp
@@ -12,17 +12,17 @@
 
 namespace td {
 
-string SpecialStickerSetType::animated_emoji() {
-  return "animated_emoji_sticker_set";
+SpecialStickerSetType SpecialStickerSetType::animated_emoji() {
+  return SpecialStickerSetType("animated_emoji_sticker_set");
 }
 
-string SpecialStickerSetType::animated_emoji_click() {
-  return "animated_emoji_click_sticker_set";
+SpecialStickerSetType SpecialStickerSetType::animated_emoji_click() {
+  return SpecialStickerSetType("animated_emoji_click_sticker_set");
 }
 
-string SpecialStickerSetType::animated_dice(const string &emoji) {
+SpecialStickerSetType SpecialStickerSetType::animated_dice(const string &emoji) {
   CHECK(!emoji.empty());
-  return PSTRING() << "animated_dice_sticker_set#" << emoji;
+  return SpecialStickerSetType(PSTRING() << "animated_dice_sticker_set#" << emoji);
 }
 
 SpecialStickerSetType::SpecialStickerSetType(
@@ -30,13 +30,13 @@ SpecialStickerSetType::SpecialStickerSetType(
   CHECK(input_sticker_set != nullptr);
   switch (input_sticker_set->get_id()) {
     case telegram_api::inputStickerSetAnimatedEmoji::ID:
-      type_ = animated_emoji();
+      *this = animated_emoji();
       break;
     case telegram_api::inputStickerSetAnimatedEmojiAnimations::ID:
-      type_ = animated_emoji_click();
+      *this = animated_emoji_click();
       break;
     case telegram_api::inputStickerSetDice::ID:
-      type_ = animated_dice(static_cast<const telegram_api::inputStickerSetDice *>(input_sticker_set.get())->emoticon_);
+      *this = animated_dice(static_cast<const telegram_api::inputStickerSetDice *>(input_sticker_set.get())->emoticon_);
       break;
     default:
       UNREACHABLE();
@@ -45,17 +45,18 @@ SpecialStickerSetType::SpecialStickerSetType(
 }
 
 string SpecialStickerSetType::get_dice_emoji() const {
-  if (begins_with(type_, "animated_dice_sticker_set#")) {
-    return type_.substr(Slice("animated_dice_sticker_set#").size());
+  auto prefix = Slice("animated_dice_sticker_set#");
+  if (begins_with(type_, prefix)) {
+    return type_.substr(prefix.size());
   }
   return string();
 }
 
 telegram_api::object_ptr<telegram_api::InputStickerSet> SpecialStickerSetType::get_input_sticker_set() const {
-  if (type_ == animated_emoji()) {
+  if (*this == animated_emoji()) {
     return telegram_api::make_object<telegram_api::inputStickerSetAnimatedEmoji>();
   }
-  if (type_ == animated_emoji_click()) {
+  if (*this == animated_emoji_click()) {
     return telegram_api::make_object<telegram_api::inputStickerSetAnimatedEmojiAnimations>();
   }
   auto emoji = get_dice_emoji();
diff --git a/td/telegram/SpecialStickerSetType.h b/td/telegram/SpecialStickerSetType.h
index 5a25c0188..fd0d2a53d 100644
--- a/td/telegram/SpecialStickerSetType.h
+++ b/td/telegram/SpecialStickerSetType.h
@@ -10,19 +10,31 @@
 
 #include "td/utils/common.h"
 
+#include <functional>
+
 namespace td {
 
-struct SpecialStickerSetType {
+class SpecialStickerSetType {
+  explicit SpecialStickerSetType(string type) : type_(type) {
+  }
+
+  friend struct SpecialStickerSetTypeHash;
+
+ public:
   string type_;
 
-  static string animated_emoji();
+  static SpecialStickerSetType animated_emoji();
 
-  static string animated_emoji_click();
+  static SpecialStickerSetType animated_emoji_click();
 
-  static string animated_dice(const string &emoji);
+  static SpecialStickerSetType animated_dice(const string &emoji);
 
   string get_dice_emoji() const;
 
+  bool is_empty() const {
+    return type_.empty();
+  }
+
   SpecialStickerSetType() = default;
 
   explicit SpecialStickerSetType(const telegram_api::object_ptr<telegram_api::InputStickerSet> &input_sticker_set);
@@ -30,4 +42,18 @@ struct SpecialStickerSetType {
   telegram_api::object_ptr<telegram_api::InputStickerSet> get_input_sticker_set() const;
 };
 
+inline bool operator==(const SpecialStickerSetType &lhs, const SpecialStickerSetType &rhs) {
+  return lhs.type_ == rhs.type_;
+}
+
+inline bool operator!=(const SpecialStickerSetType &lhs, const SpecialStickerSetType &rhs) {
+  return !(lhs == rhs);
+}
+
+struct SpecialStickerSetTypeHash {
+  std::size_t operator()(SpecialStickerSetType type) const {
+    return std::hash<string>()(type.type_);
+  }
+};
+
 }  // namespace td
diff --git a/td/telegram/StickersManager.cpp b/td/telegram/StickersManager.cpp
index 94884c77f..d9d0c8e03 100644
--- a/td/telegram/StickersManager.cpp
+++ b/td/telegram/StickersManager.cpp
@@ -1313,12 +1313,12 @@ void StickersManager::init() {
   G()->shared_config().set_option_empty("animated_dice_sticker_set_name");  // legacy
 }
 
-StickersManager::SpecialStickerSet &StickersManager::add_special_sticker_set(const string &type) {
+StickersManager::SpecialStickerSet &StickersManager::add_special_sticker_set(const SpecialStickerSetType &type) {
   auto &result = special_sticker_sets_[type];
-  if (result.type_.type_.empty()) {
-    result.type_.type_ = type;
+  if (result.type_.is_empty()) {
+    result.type_ = type;
   } else {
-    CHECK(result.type_.type_ == type);
+    CHECK(result.type_ == type);
   }
   return result;
 }
@@ -1367,7 +1367,7 @@ void StickersManager::load_special_sticker_set_by_type(const SpecialStickerSetTy
     return;
   }
 
-  auto &sticker_set = add_special_sticker_set(type.type_);
+  auto &sticker_set = add_special_sticker_set(type);
   CHECK(sticker_set.is_being_loaded_);
   sticker_set.is_being_loaded_ = false;
   load_special_sticker_set(sticker_set);
@@ -1407,7 +1407,7 @@ void StickersManager::on_load_special_sticker_set(const SpecialStickerSetType &t
     return;
   }
 
-  auto &special_sticker_set = add_special_sticker_set(type.type_);
+  auto &special_sticker_set = add_special_sticker_set(type);
   if (!special_sticker_set.is_being_loaded_) {
     return;
   }
@@ -1424,7 +1424,7 @@ void StickersManager::on_load_special_sticker_set(const SpecialStickerSetType &t
 
   special_sticker_set.is_being_loaded_ = false;
 
-  if (type.type_ == SpecialStickerSetType::animated_emoji()) {
+  if (type == SpecialStickerSetType::animated_emoji()) {
     auto promises = std::move(pending_get_animated_emoji_queries_);
     reset_to_empty(pending_get_animated_emoji_queries_);
     for (auto &promise : promises) {
@@ -1438,7 +1438,7 @@ void StickersManager::on_load_special_sticker_set(const SpecialStickerSetType &t
   CHECK(sticker_set != nullptr);
   CHECK(sticker_set->was_loaded);
 
-  if (type.type_ == SpecialStickerSetType::animated_emoji_click()) {
+  if (type == SpecialStickerSetType::animated_emoji_click()) {
     auto pending_get_requests = std::move(pending_get_animated_emoji_click_stickers_);
     reset_to_empty(pending_get_animated_emoji_click_stickers_);
     for (auto &pending_request : pending_get_requests) {
@@ -2222,7 +2222,7 @@ StickerSetId StickersManager::get_sticker_set_id(const tl_object_ptr<telegram_ap
     case telegram_api::inputStickerSetAnimatedEmoji::ID:
     case telegram_api::inputStickerSetAnimatedEmojiAnimations::ID:
       LOG(ERROR) << "Receive special sticker set " << to_string(set_ptr);
-      return add_special_sticker_set(SpecialStickerSetType(set_ptr).type_).id_;
+      return add_special_sticker_set(SpecialStickerSetType(set_ptr)).id_;
     case telegram_api::inputStickerSetDice::ID:
       LOG(ERROR) << "Receive special sticker set " << to_string(set_ptr);
       return StickerSetId();
@@ -2251,7 +2251,7 @@ StickerSetId StickersManager::add_sticker_set(tl_object_ptr<telegram_api::InputS
     case telegram_api::inputStickerSetAnimatedEmoji::ID:
     case telegram_api::inputStickerSetAnimatedEmojiAnimations::ID:
       LOG(ERROR) << "Receive special sticker set " << to_string(set_ptr);
-      return add_special_sticker_set(SpecialStickerSetType(set_ptr).type_).id_;
+      return add_special_sticker_set(SpecialStickerSetType(set_ptr)).id_;
     case telegram_api::inputStickerSetDice::ID:
       LOG(ERROR) << "Receive special sticker set " << to_string(set_ptr);
       return StickerSetId();
@@ -2438,7 +2438,7 @@ StickerSetId StickersManager::on_get_input_sticker_set(FileId sticker_file_id,
     }
     case telegram_api::inputStickerSetAnimatedEmoji::ID:
     case telegram_api::inputStickerSetAnimatedEmojiAnimations::ID:
-      return add_special_sticker_set(SpecialStickerSetType(set_ptr).type_).id_;
+      return add_special_sticker_set(SpecialStickerSetType(set_ptr)).id_;
     case telegram_api::inputStickerSetDice::ID:
       return StickerSetId();
     default:
@@ -3017,7 +3017,7 @@ void StickersManager::on_get_special_sticker_set(const SpecialStickerSetType &ty
 
   LOG(INFO) << "Receive special sticker set " << type.type_ << ": " << sticker_set_id << ' ' << s->access_hash << ' '
             << s->short_name;
-  auto &sticker_set = add_special_sticker_set(type.type_);
+  auto &sticker_set = add_special_sticker_set(type);
   if (sticker_set_id == sticker_set.id_ && s->access_hash == sticker_set.access_hash_ &&
       s->short_name == sticker_set.short_name_ && !s->short_name.empty()) {
     on_load_special_sticker_set(type, Status::OK());
@@ -3031,7 +3031,7 @@ void StickersManager::on_get_special_sticker_set(const SpecialStickerSetType &ty
 
   G()->td_db()->get_binlog_pmc()->set(type.type_, PSTRING() << sticker_set.id_.get() << ' ' << sticker_set.access_hash_
                                                             << ' ' << sticker_set.short_name_);
-  if (type.type_ == SpecialStickerSetType::animated_emoji()) {
+  if (type == SpecialStickerSetType::animated_emoji()) {
     G()->shared_config().set_option_string(PSLICE() << type.type_ << "_name", sticker_set.short_name_);
     try_update_animated_emoji_messages();
   } else if (!type.get_dice_emoji().empty()) {
diff --git a/td/telegram/StickersManager.h b/td/telegram/StickersManager.h
index 737d5b647..e9ee7012a 100644
--- a/td/telegram/StickersManager.h
+++ b/td/telegram/StickersManager.h
@@ -654,7 +654,7 @@ class StickersManager final : public Actor {
 
   void tear_down() final;
 
-  SpecialStickerSet &add_special_sticker_set(const string &type);
+  SpecialStickerSet &add_special_sticker_set(const SpecialStickerSetType &type);
 
   static void init_special_sticker_set(SpecialStickerSet &sticker_set, int64 sticker_set_id, int64 access_hash,
                                        string name);
@@ -782,7 +782,7 @@ class StickersManager final : public Actor {
   int32 recent_stickers_limit_ = 200;
   int32 favorite_stickers_limit_ = 5;
 
-  std::unordered_map<string, SpecialStickerSet> special_sticker_sets_;
+  std::unordered_map<SpecialStickerSetType, SpecialStickerSet, SpecialStickerSetTypeHash> special_sticker_sets_;
 
   struct StickerSetLoadRequest {
     Promise<Unit> promise;