13 Practic

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Text.RegularExpressions;
namespace ConsoleApp1
{


    class Program
    {
        static void Main(string[] args)
        {

            Regex a = new Regex(@"\s[0,1][0-9]|[2][0,1,2,3]:[0-5][0-9]:[0-5][0-9]\s");
            string s = @"
                        22:02:2000 f
                        22:21:50   t
                        23:21:59   t
                        22:61:24   f
                        ";
            Match list = a.Match(s);
            int ans = 0;
            while (list.Success)
            {
                ans++;
                list = list.NextMatch();
            }
            Console.WriteLine(ans);
        }
    }
}