using System;

using System.IO;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {       

        var list = new List<MailTemplate>(){

            new MailTemplate(){ TimeFirstMailWasSent = new DateTime(2020,3,25,8,45,0), AllredySentMails=10 },

            new MailTemplate(){ TimeFirstMailWasSent = new DateTime(2020,3,25,8,30,0), AllredySentMails=20 },

            new MailTemplate(){ TimeFirstMailWasSent = new DateTime(2020,3,25,9,45,0), AllredySentMails=30 },

            new MailTemplate(){ TimeFirstMailWasSent = new DateTime(2020,3,20,10,0,0), AllredySentMails=40 },

            new MailTemplate(){ TimeFirstMailWasSent = new DateTime(2020,3,24,11,30,0), AllredySentMails=50 },

        };

        var sentMailsToday = list.Where(m => m.TimeFirstMailWasSent.Date >= DateTime.Now.Date)

                                .Sum(m => m.AllredySentMails);

        Console.WriteLine(sentMailsToday);

    }

    public class MailTemplate{

        public DateTime TimeFirstMailWasSent {get;set;}

        public int AllredySentMails {get;set;}

    }

}