#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,s=1;
    cin>>n;
    for(int i=1;i<=n;i++){
        s=s*i;
    }
    cout<<s;
    return 0;
}
/**************************************************************
	Problem: 1004
	User: wuhanyu
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/