diff --git a/du4/program.c b/du4/program.c
index 6b4ddaf..8b65b66 100644
--- a/du4/program.c
+++ b/du4/program.c
@@ -3,9 +3,7 @@
 #include <string.h>
 #include <math.h>
 
-using System;
-
-class Program {
+int Program() {
     static void Main(string[] args) {
         int ch = Console.Read();
         string priklad = "";