diff --git a/basic/sn.c b/basic/sn.c
index f35ce36..359df18 100644
--- a/basic/sn.c
+++ b/basic/sn.c
@@ -35,6 +35,6 @@ const char* sn_get_str() {
   static char sn_str[32];
 
 
-  sprintf(sn_str, "%s%02ld%02ld%04ld", "SN", info->year, info->weak, info->index);
+  sprintf(sn_str, "%s%02d%02d%04d", "SN", info->year, info->weak, info->index);
   return sn_str;
 }