/in/foo.cc: In function 'int main()':
/in/foo.cc:11:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<sn1.size();i++)
              ~^~~~~~~~~~~
/in/foo.cc:13:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<sn2.size();i++)
              ~^~~~~~~~~~~
/in/foo.cc:16:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(la<=sn1.size()){
        ~~^~~~~~~~~~~~
/in/foo.cc:15:6: warning: unused variable 'j' [-Wunused-variable]
  int j=0,la=1;
      ^
/in/foo.cc:25:6: warning: unused variable 'i' [-Wunused-variable]
  int i=la;
      ^