diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index d8ce375..d983a00 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -233,7 +233,7 @@
      *       sync up their system time every 6000/360/2~=8 hours.
      */
     client_age = obfuscated_ticket_age - session->ticket_age_add;
-    age_diff = server_age - (mbedtls_ms_time_t)client_age;
+    age_diff = server_age - (mbedtls_ms_time_t) client_age;
     if (age_diff < -MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE ||
         age_diff > MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE) {
         MBEDTLS_SSL_DEBUG_MSG(