#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
const int N = 100010;
int a[N], sum[N];
void carry (int s[]) {
	for (int i = 0; i < N; i++ ) {
		if (s[i] >= 10) {
			s[i + 1] += s[i] / 10;
			s[i] %= 10;
		}
	}
}
int main() {
	int n;
	cin >> n;
	a[0] = 1;
	sum[0] = 1;
	for (int i = 2; i <= n; i++ ) {
		for (int j = 0; j < N; j++ ) {
			a[j] *=  i;
			sum[j] += a[j];
		}
		carry(a);
		carry(sum);
	}
	bool flag = true;
	for (int i = N; i >= 0; i--) {
		if (flag && !a[i]) continue;
		else {
			flag = false;
			cout << sum[i];
		}
	}
	puts("");
	return 0;
}