/in/foo.cc: In function 'int main()':
/in/foo.cc:38:28: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   38 |         if(y%4==0||y%400==0&&y%100!=0) cout << r(m,d);
      |                    ~~~~~~~~^~~~~~~~~~
/in/foo.cc:37:13: warning: unused variable 'sum' [-Wunused-variable]
   37 |         int sum = 0;
      |             ^~~