/in/foo.cc: In function 'void dts::tr_dfs1(dts::ll, dts::ll)':
/in/foo.cc:29:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (ll i=0;i<tr[now].s.size();i++)
                     ~^~~~~~~~~~~~~~~~~
/in/foo.cc: In function 'void dts::tr_dfs2(dts::ll)':
/in/foo.cc:41:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (ll i=0;i<tr[now].s.size();i++)
                     ~^~~~~~~~~~~~~~~~~