#include<bits/stdc++.h>
using namespace std;
int n,m;
int main(){
	int n,m=1; 
	cin>>n;
    for(int i=1;i<=n;i++)
    	m*=i;
	cout<<m;
	return 0;
}
/**************************************************************
	Problem: 1004
	User: zkl
	Language: C++
	Result: Accepted
	Time:6 ms
	Memory:2072 kb
****************************************************************/