foo.cc: In function ‘int main()’:
foo.cc:17:38: error: ‘s’ was not declared in this scope
   17 |                         if(a[j]=='1')s++;
      |                                      ^
foo.cc:18:20: error: ‘s’ was not declared in this scope
   18 |                 if(s<=2)ans++;
      |                    ^
foo.cc:18:25: error: ‘ans’ was not declared in this scope; did you mean ‘abs’?
   18 |                 if(s<=2)ans++;
      |                         ^~~
      |                         abs