/in/foo.c:4:6: warning: return type of 'main' is not 'int' [-Wmain]
 void main() {
      ^~~~
/in/foo.c: In function 'main':
/in/foo.c:15:10: warning: too many arguments for format [-Wformat-extra-args]
   printf("YES\n", num);
          ^~~~~~~
/in/foo.c:19:10: warning: too many arguments for format [-Wformat-extra-args]
   printf("NO\n", num);
          ^~~~~~