#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,ans=1;
	cin>>n;
	for(int i=1;i<=n;i++){
		ans*=i;
	} 
	cout<<ans;
    return 0;
}

/**************************************************************
	Problem: 1004
	User: liujinhao
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/