1
2
3

1
2
6

import java.io.*;
import java.math.BigInteger;
import java.util.*;

public class Main
{

	public static void main(String[] args)
	{
		Scanner input = new Scanner(System.in);
		while(input.hasNext())
		{
			int n = input.nextInt();
			BigInteger p = BigInteger.ONE;
			for(int i=1;i<=n;i++)
			{
				p=p.multiply(BigInteger.valueOf(i));
			}
			System.out.println(p);
		}
	}

}