/in/foo.cc: In function 'void solve2()':
/in/foo.cc:30:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(s.find(b)==-1)break;
      ~~~~~~~~~^~~~
/in/foo.cc:35:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(s.find(r1)==-1)break;
      ~~~~~~~~~~^~~~
/in/foo.cc:38:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<s.size();i++)
              ~^~~~~~~~~
/in/foo.cc: In function 'void solve3()':
/in/foo.cc:48:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<a.size();i++)
              ~^~~~~~~~~