diff --git a/du4/program.c b/du4/program.c
index 93dab6b..9f42328 100644
--- a/du4/program.c
+++ b/du4/program.c
@@ -40,9 +40,10 @@ int main() {
         while (*start != '\0') {
             if (*start != '\n' && (*start < '0' || *start > '9') && *start != '.' && *start != ' ') {
                 valid = 0;
-                break;
+                printf("CHYBA\n");
+                start++;
+            break;
             }
-            start++;
         }
 
         float result=0;