/in/foo.cc: In function 'int main()':
/in/foo.cc:53:17: warning: unused variable 'sum' [-Wunused-variable]
   flag=true;int sum=0;
                 ^~~
/in/foo.cc:59:13: warning: unused variable 'ans' [-Wunused-variable]
   long long ans;int hu=0;
             ^~~