51nod-1008 N的阶乘 mod P

https://www.51nod.com/onlineJudge/questionCode.html#!problemId=1008

拿这题回顾了快速幂，a^b  % c    ==  (  a%c * b %c   )%c;

#include <iostream>
#include <stdio.h>
using namespace std;
long long sum=1;
int main()
{
int n,p;
cin>>n>>p;
for(int i=1;i<=n;i++)
{
sum*=i%p;
sum%=p;
}
cout<<sum<<endl;
return 0;
}