#include <iostream>
#include <cstdio>
#include <cmath>
#define MAX 50000
using namespace std;
int n,num[MAX] = {1},c = 1;
int main() {
    scanf("%d",&n);
    for(int i = 2;i <= n;i ++) {
        int d = 0;
        for(int j = 0;j < c;j ++) {
            d += num[j] * i;
            num[j] = d % 10;
            d /= 10;
        }
        while(d) {
            num[c ++] = d % 10;
            d /= 10;
        }
    }
    for(int i = c - 1;i >= 0;i --) {
        printf("%d",num[i]);
    }
}