find armstrong

using System.IO;
using System;
using System.Math;
class Program
{
    static void Main()
    {
        Console.WriteLine("Hello, World!");
        int n, temp, dem=0, i, sum;
        Console.WriteLine("Nhap so N: ");
        n = int.Parse(Console.ReadLine());
        temp=n;
        while(temp>0)
        {
            temp=temp/10;
            dem++;
        }
        while(n>0)
        {
            i=n%10;
            n=n/10;
            sum=sum+pow(i,dem);
        }
        if(sum==n)
        Console.WrileLine("{0} la so Armstrong",n);
        else
        Console.WrileLine("{0} khong la so Armstrong",n);
        Console.ReadKey;
    }
}