/in/foo.cc: In function 'int main()':
/in/foo.cc:32:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<a[node].size();i++) {
                     ~^~~~~~~~~~~~~~~
/in/foo.cc:46:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<fa[node].size();i++) {
                     ~^~~~~~~~~~~~~~~~