/in/foo.cc: In function 'int main()':
/in/foo.cc:17:12: warning: iteration 2999999 invokes undefined behavior [-Waggressive-loop-optimizations]
      sum[i]=sum[i-1]*i%Mod;
      ~~~~~~^~~~~~~~~~~~~~~
/in/foo.cc:16:25: note: within this loop
     for(long long i=1; i<=3000000; i++){
                        ~^~~~~~~~~