/in/foo.cc: In function 'int main()':
/in/foo.cc:10:9: warning: iteration 999998 invokes undefined behavior [-Waggressive-loop-optimizations]
   num[i]=((num[i-1]%p)*(i%p))%p;;
         ^
/in/foo.cc:9:15: note: within this loop
  for (ll i=2;i<=1000000;i++)
              ~^~~~~~~~~