foo.cpp: In constructor '_init_::_init_()':
foo.cpp:38:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 struct _init_{_init_(){po[0]=1;for(int i=1;i<N;i++)po[i]=po[i-1]*bas;}}_;
                                            ~^~
foo.cpp: In function 'void work(int)':
foo.cpp:105:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  if(s[x]==fr[1])s1[1%m]++;
     ~~~~^~~~~~~