Problem:
Score : 400 points

Problem Statement

Joisino is planning to record N TV programs with recorders.

The TV can receive C channels numbered 1 through C.

The i-th program that she wants to record will be broadcast from time s_i to time t_i (including time s_i but not t_i) on Channel c_i.

Here, there will never be more than one program that are broadcast on the same channel at the same time.

When the recorder is recording a channel from time S to time T (including time S but not T), it cannot record other channels from time S-0.5 to time T (including time S-0.5 but not T).

Find the minimum number of recorders required to record the channels so that all the N programs are completely recorded.

Constraints

1≤N≤10^5

1≤C≤30

1≤s_i<t_i≤10^5

1≤c_i≤C

If c_i=c_j and i≠j, either t_i≤s_j or s_i≥t_j.

All input values are integers.

Input

Input is given from Standard Input in the following format:

N C
s_1 t_1 c_1
:
s_N t_N c_N

Output

When the minimum required number of recorders is x, print the value of x.

Sample Input 1

3 2
1 7 2
7 8 1
8 12 1

Sample Output 1

2

Two recorders can record all the programs, for example, as follows:

With the first recorder, record Channel 2 from time 1 to time 7. The first program will be recorded. Note that this recorder will be unable to record other channels from time 0.5 to time 7.

With the second recorder, record Channel 1 from time 7 to time 12. The second and third programs will be recorded. Note that this recorder will be unable to record other channels from time 6.5 to time 12.

Sample Input 2

3 4
1 3 2
3 4 4
1 4 3

Sample Output 2

3

There may be a channel where there is no program to record.

Sample Input 3

9 4
56 60 4
33 37 2
89 90 3
32 43 1
67 68 3
49 51 3
31 32 3
70 71 1
11 12 3

Sample Output 3

2

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
import java.io.*;
public class Main {
	public static void main(String[] args) {
		Solver solver = new Solver();
		solver.solve();
		solver.exit();
	}

	static class FastScanner {
		private final InputStream in = System.in;
		private final byte[] buffer = new byte[1024];
		private int ptr = 0;
		private int buflen = 0;
		private boolean hasNextByte() {
			if (ptr < buflen) {
				return true;
			}else{
				ptr = 0;
				try {
					buflen = in.read(buffer);
				} catch (IOException e) {
					e.printStackTrace();
				}
				if (buflen <= 0) {
					return false;
				}
			}
			return true;
		}
		private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
		private boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
		private void skipUnprintable() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;}
		public boolean hasNext() { skipUnprintable(); return hasNextByte();}
		public String next() {
			if (!hasNext()) throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int b = readByte();
			while(isPrintableChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		}
		public long nextLong() {
			if (!hasNext()) throw new NoSuchElementException();
			long n = 0;
			boolean minus = false;
			int b = readByte();
			if (b == '-') {
				minus = true;
				b = readByte();
			}
			if (b < '0' || '9' < b) {
				throw new NumberFormatException();
			}
			while(true){
				if ('0' <= b && b <= '9') {
					n *= 10;
					n += b - '0';
				}else if(b == -1 || !isPrintableChar(b)){
					return minus ? -n : n;
				}else{
					throw new NumberFormatException();
				}
				b = readByte();
			}
		}
	}

	static class Solver {
		FastScanner sc = new FastScanner();
		public Solver() { }

		String ns() { return sc.next(); }
		String[] ns(int n) {
			String a[] = new String[n];
			for(int i = 0; i < n; i ++) { a[i] = ns(); }
			return a;
		}
		String[][] ns(int n, int m) {
			String a[][] = new String[n][m];
			for(int i = 0; i < n; i ++) { a[i] = ns(m); }
			return a;
		}
		char[] nc(int n) {
			char a[] = new char[n];
			String str = ns();
			for(int i = 0; i < n; i ++) { a[i] = str.charAt(i); }
			return a;
		}
		char[][] nc(int n, int m) {
			char a[][] = new char[n][m];
			for(int i = 0; i < n; i ++) { a[i] = nc(m); }
			return a;
		}
		boolean[] nb(int n, char t) {
			boolean a[] = new boolean[n];
			char c[] = nc(n);
			for(int i = 0; i < n; i ++) { a[i] = c[i] == t; }
			return a;
		}
		boolean[][] nb(int n, int m, char t) {
			boolean a[][] = new boolean[n][m];
			for(int i = 0; i < n; i ++) { a[i] = nb(m, t); }
			return a;
		}
		int ni() { return (int)sc.nextLong(); }
		int[] ni(int n) {
			int a[] = new int[n];
			for(int i = 0; i < n; i ++) { a[i] = ni(); }
			return a;
		}
		int[][] ni(int n, int m) {
			int a[][] = new int[n][m];
			for(int i = 0; i < n; i ++) { a[i] = ni(m); }
			return a;
		}
		long nl() { return sc.nextLong(); }
		long[] nl(int n) {
			long a[] = new long[n];
			for(int i = 0; i < n; i ++) { a[i] = nl(); }
			return a;
		}
		long[][] nl(int n, int m) {
			long a[][] = new long[n][m];
			for(int i = 0; i < n; i ++) { a[i] = nl(m); }
			return a;
		}

		PrintWriter out = new PrintWriter(System.out);
		PrintWriter err = new PrintWriter(System.err);
		void prt() { out.print(""); }
		void prt(int a) { out.print(a); }
		void prt(long a) { out.print(a); }
		void prt(double a) { out.print(a); }
		void prt(String a) { out.print(a); }
		void prtln() { out.println(""); }
		void prtln(int a) { out.println(a); }
		void prtln(long a) { out.println(a); }
		void prtln(double a) { out.println(a); }
		void prtln(String a) { out.println(a); }
		void prtln(int... a) { for(int element : a){ prt(element+" "); } prtln(); }
		void prtln(long... a) { for(long element : a){ prt(element+" "); } prtln(); }
		void prtln(double... a) { for(double element : a){ prt(element+" "); } prtln(); }
		void prtln(String... a) { for(String element : a){ prt(element+" "); } prtln(); }
		void prtln(int[][] a) { for(int[] element : a){ prtln(element); } }
		void prtln(long[][] a) { for(long[] element : a){ prtln(element); } }
		void prtln(double[][] a) { for(double[] element : a){ prtln(element); } }
		void prtln(String[][] a) { for(String[] element : a){ prtln(element); } }
		void errprt() { err.print(""); }
		void errprt(int a) { err.print(a); }
		void errprt(long a) { err.print(a); }
		void errprt(double a) { err.print(a); }
		void errprt(String a) { err.print(a); }
		void errprt(boolean a) { errprt(a ? "#" : "."); }
		void errprtln() { err.println(""); }
		void errprtln(int a) { err.println(a); }
		void errprtln(long a) { err.println(a); }
		void errprtln(double a) { err.println(a); }
		void errprtln(String a) { err.println(a); }
		void errprtln(boolean a) { errprtln(a ? "#" : "."); }
		void errprtln(int... a) { for(int element : a){ errprt(element+" "); } errprtln(); }
		void errprtln(long... a) { for(long element : a){ errprt(element+" "); } errprtln(); }
		void errprtln(double... a) { for(double element : a){ errprt(element+" "); } errprtln(); }
		void errprtln(String... a) { for(String element : a){ errprt(element+" "); } errprtln(); }
		void errprtln(boolean... a) { for(boolean element : a){ errprt(element); } errprtln(); }
		void errprtln(int[][] a) { for(int[] element : a){ errprtln(element); } }
		void errprtln(long[][] a) { for(long[] element : a){ errprtln(element); } }
		void errprtln(double[][] a) { for(double[] element : a){ errprtln(element); } }
		void errprtln(String[][] a) { for(String[] element : a){ errprtln(element); } }
		void errprtln(boolean[][] a) { for(boolean[] element : a){ errprtln(element); } }
		void reply(boolean b) { prtln(b ? "Yes" : "No"); }
		void REPLY(boolean b) { prtln(b ? "YES" : "NO"); }

		void exit() { out.flush(); err.flush(); System.exit(0); }

		int min(int a, int b) { return Math.min(a, b); }
		long min(long a, long b) { return Math.min(a, b); }
		double min(double a, double b) { return Math.min(a, b); }
		int min(int... x) {
			int min = x[0];
			for(int val : x) { min = min(min, val); }
			return min;
		}
		long min(long... x) {
			long min = x[0];
			for(long val : x) { min = min(min, val); }
			return min;
		}
		double min(double... x) {
			double min = x[0];
			for(double val : x) { min = min(min, val); }
			return min;
		}
		int max(int a, int b) { return Math.max(a, b); }
		long max(long a, long b) { return Math.max(a, b); }
		double max(double a, double b) { return Math.max(a, b); }
		int max(int... x) {
			int max = x[0];
			for(int val : x) { max = max(max, val); }
			return max;
		}
		long max(long... x) {
			long max = x[0];
			for(long val : x) { max = max(max, val); }
			return max;
		}
		double max(double... x) {
			double max = x[0];
			for(double val : x) { max = max(max, val); }
			return max;
		}
		long sum(int... a) {
			long sum = 0;
			for(int element : a) { sum += element; }
			return sum;
		}
		long sum(long... a) {
			long sum = 0;
			for(long element : a) { sum += element; }
			return sum;
		}
		double sum(double... a) {
			double sum = 0;
			for(double element : a) { sum += element; }
			return sum;
		}

		long abs(double x) { return (long)Math.abs(x); }
		long round(double x) { return Math.round(x); }
		long floor(double x) { return (long)Math.floor(x); }
		long ceil(double x) { return (long)Math.ceil(x); }
		double sqrt(double x) { return Math.sqrt(x); }
		double pow(double x, double y) { return Math.pow(x, y); }
		long pow(long x, long y) { return (long)Math.pow(x, y); }
		int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }
		long gcd(long a, long b) { return b == 0 ? a : gcd(b, a % b); }

		void fill(int array[], int x) { Arrays.fill(array, x); }
		void fill(long array[], long x) { Arrays.fill(array, x); }
		void fill(double array[], double x) { Arrays.fill(array, x); }
		void fill(boolean array[], boolean x) { Arrays.fill(array, x); }
		void fill(int array[][], int x) { for(int a[] : array) { fill(a, x); } }
		void fill(long array[][], long x) { for(long a[] : array) { fill(a, x); } }
		void fill(double array[][], double x) { for(double a[] : array) { fill(a, x); } }
		void fill(boolean array[][], boolean x) { for(boolean a[] : array) { fill(a, x); } }

		long INF = (long)1e+15;
		boolean isINF(long a) { return abs(a) > INF / 1000; }
		boolean isPlusINF(long a) { return a > 0 && isINF(a); }
		boolean isMinusINF(long a) { return isPlusINF(- a); }


		// mods
		long MOD = pow(10, 9) + 7;
		public long mod(long i) { return i % MOD + ((i % MOD) < 0 ? MOD : 0); }
		
		long pow_m(long x, long y) {
			if (y == 0) { return 1;
			}else {
				long tmp = pow_m(x, y / 2);
				return mod(mod(tmp * tmp) * (y % 2 == 0 ? 1 : x));
			}
		}
		
		long inv(long x) { return pow_m(x, MOD - 2); }
		
		int MAX_FACT = 5_000_100;
		long fact[];
		long invFact[];
		void prepareFact() {
			fact = new long[MAX_FACT];
			Arrays.fill(fact, 0);
			invFact = new long[MAX_FACT];
			Arrays.fill(invFact, 0);
			fact[0] = 1;
			int maxIndex = min(MAX_FACT, (int)MOD);
			for(int i = 1; i < maxIndex; i ++) { fact[i] = mod(fact[i - 1] * i); }
			invFact[maxIndex - 1] = inv(fact[maxIndex - 1]);
			for(int i = maxIndex - 1; i > 0; i --) { invFact[i - 1] = mod(invFact[i] * i); }
		}
		
		long P(int n, int r) {
			if(n < 0 || r < 0 || n < r) { return 0; }
			return mod(fact[n] * invFact[n - r]);
		}
		long C(int n, int r) {
			if(n < 0 || r < 0 || n < r) { return 0; }
			return mod(P(n, r) * invFact[r]);
		}
		long H(int n, int r) { return C((n - 1) + r, r); }

		// grid
		class Grid {
			int h;
			int w;

			Grid() {  }
			Grid(int h, int w) {
				this.h = h;
				this.w = w;
			}
		}


		// graph
		class Graph {
			int numNode;
			int numEdge;
			Edge edges[];
			Node nodes[];
			Node reversedNodes[];

			Graph(int numNode, int numEdge, Edge edges[], boolean directed) {
				this.numNode = numNode;
				this.numEdge = numEdge;
				this.edges = edges;
				nodes = new Node[numNode];
				reversedNodes = new Node[numNode];
				for(int i = 0; i < numNode; i ++) {
					nodes[i] = new Node(i);
					reversedNodes[i] = new Node(i);
				}

				for(Edge edge : edges) {
					nodes[edge.source].add(edge.target, edge.cost);
					if(directed) {
						reversedNodes[edge.target].add(edge.source, edge.cost);
					}else {
						nodes[edge.target].add(edge.source, edge.cost);
					}
				}
			}

			void clearNodes() {
				for(Node n : nodes) { n.clear(); }
				for(Node n : reversedNodes) { n.clear(); }
			}
		}

		class Node {
			int id;
			ArrayList<Edge> edges = new ArrayList<Edge>();

			Node(int id) {
				this.id = id;
			}
			void add(int target, long cost) {
				edges.add(new Edge(id, target, cost));
			}
			void clear() {
				edges.clear();
			}
		}

		class Edge implements Comparable<Edge> {
			int source;
			int target;
			long cost;
			Edge(int source, int target, long cost) {
				this.source = source;
				this.target = target;
				this.cost = cost;
			}

			@Override
			public int compareTo(Edge e) {
				return Long.compare(this.cost, e.cost);
			}
		}

long[] dijkstra(Node nodes[], int start) {
	long dist[] = new long[nodes.length];
	Arrays.fill(dist, INF);
	dist[start] = 0;

	Queue<Edge> q = new PriorityQueue<Edge>();
	q.add(new Edge(start, start, dist[start]));

	while(!q.isEmpty()) {
		Edge crt = q.poll();

		if(dist[crt.target] < crt.cost) { continue; }
		for(Edge e : nodes[crt.target].edges) {
			if(dist[e.target] > dist[e.source] + e.cost) {
				dist[e.target] = dist[e.source] + e.cost;
				q.add(new Edge(e.source, e.target, dist[e.target]));
			}
		}
	}

	return dist;
}

public void solve() {
	int num = ni();
	int channel = ni();
	int array[][] = ni(num, 3);
	Arrays.sort(array, (a, b) -> Integer.compare(a[1], b[1]));
	Arrays.sort(array, (a, b) -> Integer.compare(a[0], b[0]));
	Arrays.sort(array, (a, b) -> Integer.compare(a[2], b[2]));
	for(int i = 1; i < num; i ++) {
		if(array[i][2] == array[i - 1][2] && array[i][0] == array[i - 1][1]) {
			array[i][0] = array[i - 1][0];
			array[i - 1][0] = -(int)1e+5;
			array[i - 1][1] = -(int)1e+5;
		}
	}
	for(int i = 0; i < num; i ++) {
		array[i][0] --;
	}
	long count[] = new long[(int)1e+5 + 100];
	for(int i = 0; i < num; i ++) {
		if(array[i][0] >= 0) {
			count[array[i][0]] ++;
			count[array[i][1]] --;
		}
	}
	for(int i = 1; i < count.length; i ++) {
		count[i] += count[i - 1];
	}
	prtln(max(count));
}



	}
}