#include<bits/stdc++.h>
using namespace std;
int n;

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin>>n;int ans=1;
	for(int i=1;i<=n;i++){
		ans*=i;
	}
	cout<<ans;
	return 0;
}

/**************************************************************
	Problem: 1004
	User: liangshinan
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2228 kb
****************************************************************/