/in/foo.cc: In function 'void solve2()':
/in/foo.cc:40:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(s.find(b)==-1)break;
      ~~~~~~~~~^~~~
/in/foo.cc:45:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(s.find(r3)==-1)break;
      ~~~~~~~~~~^~~~
/in/foo.cc: In function 'void solve3()':
/in/foo.cc:58:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<a.size();i++)
              ~^~~~~~~~~