diff --git a/du3/program.c b/du3/program.c
index 1781b5a..570db07 100644
--- a/du3/program.c
+++ b/du3/program.c
@@ -82,6 +82,8 @@ int main(){
 		}
 		print (&mystack);
 	}
-		
+	if(mystack.size == 0){
+		printf("no input\n");
+	}		
 	return 0;	
 }