foo.cc: In function 'int bfs(int)':
foo.cc:22:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |         for(int i=0;i<p[t].nxt.size();++i)
      |                     ~^~~~~~~~~~~~~~~~
foo.cc: In function 'void dfs(int, int)':
foo.cc:31:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |     for(int i=0;i<p[x].nxt.size();++i)
      |                 ~^~~~~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:50:18: warning: unused variable 'ans' [-Wunused-variable]
   50 |     int x=bfs(0),ans=0;
      |                  ^~~
foo.cc:42:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   42 |     scanf("%d",&n);
      |     ~~~~~^~~~~~~~~
foo.cc:46:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   46 |         scanf("%d%d",&u,&v);
      |         ~~~~~^~~~~~~~~~~~~~

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