#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: liyunshuo
	Language: C++
	Result: Accepted
	Time:11 ms
	Memory:2072 kb
****************************************************************/