/in/foo.cc: In function 'int main()':
/in/foo.cc:90:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   int mid=l+r>>1;
           ~^~
/in/foo.cc:91:18: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   if(P=check(mid))ans=mid,ans1=P,l=mid+1;
                  ^