/in/foo.cc: In function 'int main()':
/in/foo.cc:13:15: warning: array subscript has type 'char' [-Wchar-subscripts]
   13 |         a[s[0]][int(s[1])]=1;
      |               ^
/in/foo.cc:7:5: warning: label 'std' defined but not used [-Wunused-label]
    7 |     std:ios::sync_with_stdio(false);
      |     ^~~