diff --git a/du4/program.c b/du4/program.c
index 7247876..dc7790e 100644
--- a/du4/program.c
+++ b/du4/program.c
@@ -77,25 +77,25 @@ int main() {
 
         switch(operation){
             case 1:
-                if(strtof(number1, &ptr) != roundf(strtof(number1, &ptr)))
+                if((strtof(number1, &ptr) != roundf(strtof(number1, &ptr))) || (strtof(number2, &ptr) != roundf(strtof(number2, &ptr))) || (strtof(result, &ptr) != roundf(strtof(result, &ptr))))
                     printf("%s\n", (roundf((strtof(number1, &ptr) + strtof(number2, &ptr))*100)/100 > strtof(result, &ptr) - 0.001 && roundf((strtof(number1, &ptr) + strtof(number2, &ptr))*100)/100 < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
                 else
                     printf("%s\n", (strtof(number1, &ptr) + strtof(number2, &ptr) > strtof(result, &ptr) - 0.001 && strtof(number1, &ptr) + strtof(number2, &ptr) < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
                 break;
             case 2:
-                if(strtof(number1, &ptr) != roundf(strtof(number1, &ptr)))
+                if((strtof(number1, &ptr) != roundf(strtof(number1, &ptr))) || (strtof(number2, &ptr) != roundf(strtof(number2, &ptr))) || (strtof(result, &ptr) != roundf(strtof(result, &ptr))))
                     printf("%s\n", (roundf((strtof(number1, &ptr) - strtof(number2, &ptr))*100)/100 > strtof(result, &ptr) - 0.001 && roundf((strtof(number1, &ptr) - strtof(number2, &ptr))*100)/100 < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
                 else
                     printf("%s\n", (strtof(number1, &ptr) - strtof(number2, &ptr) > strtof(result, &ptr) - 0.001 && strtof(number1, &ptr) - strtof(number2, &ptr) < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
                 break;
             case 3:
-                if(strtof(number1, &ptr) != roundf(strtof(number1, &ptr)))
+                if((strtof(number1, &ptr) != roundf(strtof(number1, &ptr))) || (strtof(number2, &ptr) != roundf(strtof(number2, &ptr))) || (strtof(result, &ptr) != roundf(strtof(result, &ptr))))
                     printf("%s\n", (roundf((strtof(number1, &ptr) * strtof(number2, &ptr))*100)/100 > strtof(result, &ptr) - 0.001 && roundf((strtof(number1, &ptr) * strtof(number2, &ptr))*100)/100 < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
                 else
                     printf("%s\n", (strtof(number1, &ptr) * strtof(number2, &ptr) > strtof(result, &ptr) - 0.001 && strtof(number1, &ptr) * strtof(number2, &ptr) < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
                 break;
             case 4:
-                if(strtof(number1, &ptr) != roundf(strtof(number1, &ptr)))
+                if((strtof(number1, &ptr) != roundf(strtof(number1, &ptr))) || (strtof(number2, &ptr) != roundf(strtof(number2, &ptr))) || (strtof(result, &ptr) != roundf(strtof(result, &ptr))))
                     printf("%s\n", (roundf((strtof(number1, &ptr) / strtof(number2, &ptr))*100)/100 > strtof(result, &ptr) - 0.001 && roundf((strtof(number1, &ptr) / strtof(number2, &ptr))*100)/100 < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
                 else
                     printf("%s\n", (strtof(number1, &ptr) / strtof(number2, &ptr) > strtof(result, &ptr) - 0.001 && strtof(number1, &ptr) / strtof(number2, &ptr) < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");