/in/foo.cc: In function 'int main()':
/in/foo.cc:30:9: warning: unused variable 'u' [-Wunused-variable]
  int r, u, v, w, ans = 0;
         ^
/in/foo.cc:30:12: warning: unused variable 'v' [-Wunused-variable]
  int r, u, v, w, ans = 0;
            ^
/in/foo.cc:30:15: warning: unused variable 'w' [-Wunused-variable]
  int r, u, v, w, ans = 0;
               ^