diff --git a/mtprotoproxy.py b/mtprotoproxy.py
index 6077746..87523fc 100755
--- a/mtprotoproxy.py
+++ b/mtprotoproxy.py
@@ -963,7 +963,6 @@ async def handle_handshake(reader, writer):
     global used_handshakes
 
     TLS_START_BYTES = b"\x16\x03\x01\x02\x00\x01\x00\x01\xfc\x03\x03"
-    TLS_START_LEN = len(TLS_START_BYTES)
     EMPTY_READ_BUF_SIZE = 4096
 
     peer = writer.get_extra_info('peername')[:2]
@@ -976,13 +975,14 @@ async def handle_handshake(reader, writer):
 
     is_tls_handshake = True
     handshake = b""
-    for byte_num in range(TLS_START_LEN):
+    for expected_byte in TLS_START_BYTES:
         handshake += await reader.readexactly(1)
-        if handshake[-1] != TLS_START_BYTES[byte_num]:
+        if handshake[-1] != expected_byte:
             is_tls_handshake = False
+            break
 
     if is_tls_handshake:
-        handshake += await reader.readexactly(TLS_HANDSHAKE_LEN - TLS_START_LEN)
+        handshake += await reader.readexactly(TLS_HANDSHAKE_LEN - len(handshake))
         tls_handshake_result = await handle_pseudo_tls_handshake(handshake, reader, writer, peer)
 
         if not tls_handshake_result:
@@ -994,7 +994,7 @@ async def handle_handshake(reader, writer):
         if config.TLS_ONLY:
             await handle_bad_client(reader, writer, handshake)
             return False
-        handshake += await reader.readexactly(HANDSHAKE_LEN - TLS_START_LEN)
+        handshake += await reader.readexactly(HANDSHAKE_LEN - len(handshake))
 
     dec_prekey_and_iv = handshake[SKIP_LEN:SKIP_LEN+PREKEY_LEN+IV_LEN]
     dec_prekey, dec_iv = dec_prekey_and_iv[:PREKEY_LEN], dec_prekey_and_iv[PREKEY_LEN:]