/in/foo.cc: In function 'void Tarjan(int)':
/in/foo.cc:20:11: warning: unused variable 'sum' [-Wunused-variable]
  int fl=0,sum=0;
           ^~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:50:16: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'long long int*' [-Wformat=]
   scanf("%d",&n);
                ^