using Yorukatsu056.Questions;
using Yorukatsu056.Extensions;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace Yorukatsu056.Questions
{
    /// <summary>
    /// https://atcoder.jp/contests/abc080/tasks/abc080_d
    /// </summary>
    public class QuestionE : AtCoderQuestionBase
    {
        public override IEnumerable<object> Solve(TextReader inputStream)
        {
            var nc = inputStream.ReadIntArray();
            var programCount = nc[0];
            var channels = nc[1];

            var programs = Enumerable.Repeat(0, channels).Select(_ => new List<TVProgram>()).ToArray();

            for (int i = 0; i < programCount; i++)
            {
                var stc = inputStream.ReadIntArray();
                var program = new TVProgram(stc[0], stc[1]);
                var channel = stc[2] - 1;
                programs[channel].Add(program);
            }

            var usedDecks = new int[100001];

            for (int channel = 0; channel < programs.Length; channel++)
            {
                var channelPrograms = programs[channel];
                channelPrograms.Sort();
                for (int prog = 0; prog < channelPrograms.Count; prog++)
                {
                    var hasPrevious = prog > 0 && channelPrograms[prog - 1].EndTime == channelPrograms[prog].StartTime;
                    if (hasPrevious)
                    {
                        usedDecks[channelPrograms[prog].StartTime]++;
                    }
                    else
                    {
                        usedDecks[channelPrograms[prog].StartTime - 1]++;
                    }

                    usedDecks[channelPrograms[prog].EndTime]--;
                }
            }

            for (int time = 0; time + 1 < usedDecks.Length; time++)
            {
                usedDecks[time + 1] += usedDecks[time];
            }

            yield return usedDecks.Max();
        }

        struct TVProgram : IComparable<TVProgram>
        {
            public int StartTime { get; }
            public int EndTime { get; }

            public TVProgram(int startTime, int endTime)
            {
                StartTime = startTime;
                EndTime = endTime;
            }

            public int CompareTo(TVProgram other) => StartTime.CompareTo(other.StartTime);
        }
    }
}


namespace Yorukatsu056
{
    class Program
    {
        static void Main(string[] args)
        {
            IAtCoderQuestion question = new QuestionE();    // 問題に合わせて書き換え
            var answers = question.Solve(Console.In);
            foreach (var answer in answers)
            {
                Console.WriteLine(answer);
            }
        }
    }
}

#region Base Classes

namespace Yorukatsu056.Questions
{

    public interface IAtCoderQuestion
    {
        IEnumerable<object> Solve(string input);
        IEnumerable<object> Solve(TextReader inputStream);
    }

    public abstract class AtCoderQuestionBase : IAtCoderQuestion
    {
        public IEnumerable<object> Solve(string input)
        {
            var stream = new MemoryStream(Encoding.Unicode.GetBytes(input));
            var reader = new StreamReader(stream, Encoding.Unicode);

            return Solve(reader);
        }

        public abstract IEnumerable<object> Solve(TextReader inputStream);
    }

}

#endregion

#region Extensions

namespace Yorukatsu056.Extensions
{
    internal static class TextReaderExtensions
    {
        internal static int ReadInt(this TextReader reader) => int.Parse(ReadString(reader));
        internal static long ReadLong(this TextReader reader) => long.Parse(ReadString(reader));
        internal static double ReadDouble(this TextReader reader) => double.Parse(ReadString(reader));
        internal static string ReadString(this TextReader reader) => reader.ReadLine();

        internal static int[] ReadIntArray(this TextReader reader, char separator = ' ') => ReadStringArray(reader, separator).Select(int.Parse).ToArray();
        internal static long[] ReadLongArray(this TextReader reader, char separator = ' ') => ReadStringArray(reader, separator).Select(long.Parse).ToArray();
        internal static double[] ReadDoubleArray(this TextReader reader, char separator = ' ') => ReadStringArray(reader, separator).Select(double.Parse).ToArray();
        internal static string[] ReadStringArray(this TextReader reader, char separator = ' ') => reader.ReadLine().Split(separator);
    }
}

#endregion

Measured memory_bytes: 19400