/in/foo.cc: In function 'void Output()':
/in/foo.cc:36:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < all_num.size(); i++) {
                  ~~^~~~~~~~~~~~~~~~
/in/foo.cc:38:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int j = 0; j < all_num[i].size(); j++) {
                   ~~^~~~~~~~~~~~~~~~~~~
/in/foo.cc:39:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int k = 0; k < all_num[i][j].size(); k++) {
                    ~~^~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc:77:17: warning: 'all_max' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout << all_max;
                 ^
/in/foo.cc:62:11: warning: 'max' may be used uninitialized in this function [-Wmaybe-uninitialized]
       max = max + all_num[i][j][k] * 9;
       ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~