#include <iostream>
#include <string>

using namespace std;

int main()
{
	int n;
	long ans = 1;

	string s[] = {
"0", 
"1", 
"2", 
"6", 
"24", 
"120", 
"720", 
"5040", 
"40320", 
"362880", 
"3628800", 
"39916800", 
"479001600", 
"6227020800", 
"87178291200", 
"1307674368000", 
"20922789888000", 
"355687428096000", 
"6402373705728000", 
"121645100408832000", 
"2432902008176640000", 
};

	while (cin >> n) {
		cout << s[n] << endl;
	}
	return 0;
}

