using System;

​

public class Program

{

    public static int factorial(int n)

    {

        int i, f = 1;

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

        {

            f = f * i;

        }

​

        return f;

    }

​

    public static void Main()

    {

        int n;

        Console.WriteLine("Dame un número entero: ");

        n = Convert.ToInt32(Console.ReadLine());

        Console.WriteLine("El factorial de " + n.ToString() + " es igual a " + factorial(n).ToString());

    }

}