#include <iostream>
#include <string>
using namespace std;

string multiplication (string x, int y) { 
	int carry = 0, temporary = 0;
	string answer = "";
	for (int i = x.size() - 1; i >= 0; i--) {
 	temporary = int(x[i] - '0') * y + carry;
	carry = temporary/10;
	answer = char(temporary % 10 + '0') + answer;
}
while (carry) {
	answer = char(carry % 10 + '0') + answer;
    carry /= 10;
}
return answer;
}
int main() {
	int n;
	string s = "1";
	cin >> n;
	for (int i = 2; i <= n; i++) {
		 s = multiplication(s, i);
	} 
	cout << s << endl;
}