/in/foo.cc: In function 'int main()':
/in/foo.cc:19:25: warning: suggest parentheses around comparison in operand of '^' [-Wparentheses]
   19 |             if(s[i]^s[j]==k)
      |                     ~~~~^~~
/in/foo.cc:7:5: warning: label 'std' defined but not used [-Wunused-label]
    7 |     std:ios::sync_with_stdio(false);
      |     ^~~