#include <bits/stdc++.h>

using namespace std;

int main(){
    #ifndef ONLINE_JUDGE
    freopen("debug.in", "r", stdin);
    #endif // ONLINE_JUDGE

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