/in/foo.cc: In function 'void dfs(std::__cxx11::string, ll)':
/in/foo.cc:61:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (ll i = 0; i < vec.size(); i++)
                 ~~^~~~~~~~~~~~
/in/foo.cc:65:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (ll j = 0; j < vv.size(); j++)
                   ~~^~~~~~~~~~~
/in/foo.cc:73:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (ll k = vec[j].first.size() + vv[j]; k < s1.size(); k++)
                                              ~~^~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:97:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (ll i = 0; i < ans.size(); i++)
                 ~~^~~~~~~~~~~~