#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,s;
    cin>>n;
	s=1;
	for(int i=1;i<=n;i++){
		s*=i;
	}
	cout<<s<<endl;
    return 0;
}
/**************************************************************
	Problem: 1004
	User: xiaojingxuan
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/