[백준] 5692번 : 팩토리얼 진법 - C#

https://www.acmicpc.net/problem/5692

using System;
using System.Text;

class Program
{
    static void Main() {
        StringBuilder sb = new StringBuilder();
        for(;;){
            int a=int.Parse(Console.ReadLine());
            if(a==0) break;
            int count=1;
            int num=1;
            int sum=0;
            while(a>0){
                int n=a%10;
                sum+=n*num;
                a/=10;
                num*=++count;
            }
            sb.Append(sum+"\n");
        }
        Console.Write(sb.ToString());
    }
}