#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,i,j=1;
	cin>>n;
	for(i=1;i<=n;i++){
		j=i*j;
	}
	cout<<j;
}
/**************************************************************
	Problem: 1004
	User: linzihang
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/