View Compilation Error

0_0_28218727_20670.cpp: In function 'void dfs(int, int)':
0_0_28218727_20670.cpp:34:6: error: 'flag' was not declared in this scope
   if(flag) return ;
      ^
0_0_28218727_20670.cpp:39:7: error: 'flag' was not declared in this scope
       flag = true;
       ^
0_0_28218727_20670.cpp: In function 'int main()':
0_0_28218727_20670.cpp:74:5: error: 'flag' was not declared in this scope
     flag = false;
     ^