/in/foo.cc: In function 'int main()':
/in/foo.cc:42:16: warning: suggest parentheses around '+' in operand of '&' [-Wparentheses]
   42 |         if ((m + n & 1) && gcd(m, n) == 1)  printf("y");
      |              ~~^~~
/in/foo.cc:36:9: warning: unused variable 'i' [-Wunused-variable]
   36 |     int i, j;
      |         ^
/in/foo.cc:36:12: warning: unused variable 'j' [-Wunused-variable]
   36 |     int i, j;
      |            ^