using System;
public class Program
{
static int TinhGiaithua(int n)
int T=1;
for (int i=2;i<=n;i++)
T=T*i;
}
return T;
public static void Main(string [] args)
int N;
Console.Write("N:");
N=int.Parse(Console.ReadLine());
int T = TinhGiaithua(N);
Console.WriteLine (T);