baekjoon 10872

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

class Main{
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder sb = new StringBuilder();
        int N = Integer.parseInt(br.readLine()), M=1;
        for (int n = 1; n <= N; n++)
            M *= n;
        sb.append(M);
        System.out.println(sb);
        br.close();
    }
}