/in/foo.cc: In function 'int main()':
/in/foo.cc:31:29: warning: iteration 1048574 invokes undefined behavior [-Waggressive-loop-optimizations]
  for( i=1;i<=MM;i++) ans+=cc(x[i])+cc(y[i]);
                           ~~^~~~~~
/in/foo.cc:31:12: note: within this loop
  for( i=1;i<=MM;i++) ans+=cc(x[i])+cc(y[i]);
           ~^~~~