設計一個程式，輸入一個日期，求該日期是這一年中的第幾天。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int years, moth, day,sum=0;
            int[] monthDays = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
            years = int.Parse(Console.ReadLine());
            moth = int.Parse(Console.ReadLine());
            day = int.Parse(Console.ReadLine());
            if (years % 400 == 0 || (years % 100 == 0 && years % 4 != 0))
            {
                monthDays[1] = 29;
            }
            Console.Write("該天是該年的第");
            for (int i = 0; i < moth; i++)
            {
                sum += monthDays[i];
            }
            Console.Write(sum + day);
            Console.WriteLine("天。");
            Console.ReadLine();
        }
    }
}