/in/foo.cc: In function 'int main()':
/in/foo.cc:34:7: warning: unused variable 'my_max' [-Wunused-variable]
   int my_max=10000000;
       ^~~~~~
/in/foo.cc:12:30: warning: unused variable 'n1' [-Wunused-variable]
  register int n,m,x,y,mmax=0,n1=0,ans=0;
                              ^~