using System; public class Program { public static void Main() { int happyDay = 0; //カウント for (int i = 0; i < 365; i++) { DateTime addDay = new DateTime(2015, 1, 1).AddDays(i); if (addDay.Month == addDay.Day) //月と日が同じ { happyDay++; continue; } else if (addDay.Day >= 10) //day10以上 { int ten = int.Parse(addDay.Day.ToString().Substring(0,1)); int one = int.Parse(addDay.Day.ToString().Substring(1)); int num = ten + one; if (addDay.Month == num) { happyDay++; continue; } } } Console.WriteLine("{0}", happyDay); } }