#include <iostream>
#include <string>
#include <algorithm>
#include <utility>
#include <iomanip>
#include <functional>
#include <queue>
#include <stack>
#include <cmath>
#define INF 100000000
#define MOD 1000000007
using namespace std;


int main(){
    int n;
    cin >> n;
    int ans=1;
    for(int i=1; i<=n; i++){
        ans*=i;
    }
    cout<<ans<<endl;
    
    return 0;
}

