/in/foo.cc: In function 'void DFS(int, int, char)':
/in/foo.cc:10:2: error: 'cnt' was not declared in this scope
  cnt++;
  ^~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:55:6: error: 'cnt' was not declared in this scope
      cnt=0;
      ^~~