using System;
using System.Collections.Generic;
					
public class Program
{
	public static void Main()
	{
		int n = int.Parse(Console.ReadLine());
		
		var S = new List<string>(n);
		for (int i=0; i<n; i++) S.Add(Console.ReadLine());
		
		var permutation = 1;
		for (int i=n; i>0; i--) permutation *= i;
		
		Console.WriteLine(permutation);
	}
}