#include <iostream>

using namespace std;

int main() {
	int n, gt = 1;
	cout<<"Nhap n: "; cin>>n;
	if (n == 0) gt = 1;
	for (int i = 1; i <= n; i++) {
		gt = gt * i;
	}
	cout<<n<<"! = "<<gt;
	return 0;
}