using System;

public class Program

{

    public static void Main()

    {

    int i,n;

    int fact=1;

        Console.WriteLine("enter the value of n");

        n=int.Parse(Console.ReadLine());

            for(i=1;i<=n;i++)

            {

                fact=fact*i;

            }

            Console.WriteLine("the factorial of {0} is {1}",n,fact);

    }

}