#include <iostream>
using namespace std;

int a[101] = {0}, s[101] = {0};


void ji(int x) {
	int g = 0;
	for (int i = 100; i >= 0; i--) {
		a[i] = a[i] * x + g;
		a[i] = a[i] % 10;
		g = a[i] / 10;
	}
}

void he() {
	int h = 0;
	for (int i = 100; i >= 0; i--) {
		s[i] = s[i] + a[i] + h;
		h = s[i] / 10;
		s[i] = s[i] % 10;
	}
}

void shu() {
	int w = 0;
	for (int i = 0; i <= 100; i++) {
		if (s[i] != 0) {
			w = i;
			break;
		}
	}
	for (int i = w; i <= 100; i++) {
		cout << s[i];
	}
}

int main() {

	int n;
	cin >> n;
	a[100] = s[100] = 1;
	for (int i = 2; i <= n; i++) {
		ji(i);
		he();
	}
	shu();



	return 0;
}