using System;
using System.Collections.Generic;
using System.Collections;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.IO;
using System.Reflection;
using static System.Math;
using System.Numerics;
using System.Threading;
using System.Runtime.CompilerServices;
using System.Diagnostics;
//using nint=System.Int32;
static class Program{
	const long inf=long.MaxValue>>1;
	const int mod=(int)1e9+7;//998244353;
	static Sc sc=new Sc();
	static Pt pt=new Pt();
	static void Main(){
		Solve();
		pt.Sm();
	}
	static void Solve() {
		var (n,m)=sc.Tp2<int>();
		var h=new (int,int)[n+1];
		var w=new (int,int)[n+1];
		var ca=new int[n+1][];
		h[0]=w[0]=(-mod,0);
		for(int i = 1;i<=n;i++) {
			var e=sc.Ia;
			ca[i]=new int[]{0,0,e[2]};
			h[i]=(e[0],i);
			w[i]=(e[1],i);
		}
		Array.Sort(h,(u,v)=>u.Item1-v.Item1);
		Array.Sort(w,(u,v)=>u.Item1-v.Item1);
		var hl=new List<int>{-mod};
		var wl=new List<int>{-mod};
		for(int i = 1,j=0,k=0;i<=n;i++) {
			if(h[i].Item1!=h[i-1].Item1){
				hl.Add(h[i].Item1);
				j++;
			}
			if(w[i].Item1!=w[i-1].Item1){
				wl.Add(w[i].Item1);
				k++;
			}
			ca[h[i].Item2][0]=j;
			ca[w[i].Item2][1]=k;
		}
		hl.Add(mod);
		wl.Add(mod);
		var bm=new long[hl.Count][];
		var bc=new int[hl.Count][];
		for(int i = 0;i<hl.Count;i++) {
			bm[i]=new long[wl.Count];
			bc[i]=new int[wl.Count];
		}
		for(int i = 1;i<=n;i++) {
			bm[ca[i][0]][ca[i][1]]=ca[i][2];
			bc[ca[i][0]][ca[i][1]]=1;
		}
		for(int i=1;i<hl.Count;i++){
			for(int j=1;j<wl.Count;j++){
				bm[i][j]+=bm[i][j-1];
				bc[i][j]+=bc[i][j-1];
			}
		}
		for(int i=1;i<wl.Count;i++){
			for(int j=1;j<hl.Count;j++){
				bm[j][i]+=bm[j-1][i];
				bc[j][i]+=bc[j-1][i];
			}
		}
		int ans=0;
		for(int i = 1;i<hl.Count-1;i++) {
			for(int j = 1;j<wl.Count-1;j++) {
				for(int l = wl.Count-2,k=i;l>=j&&k<hl.Count-1;l--) {
					while(k<hl.Count-1&&Fm(i,j,k,l)<=m){
						ans=Max(ans,Fc(i,j,k,l));
						k++;
					}
				}
			}
		}
		long Fm(int a,int b,int c,int d) {return bm[c][d]+bm[a-1][b-1]-bm[c][b-1]-bm[a-1][d];}
		int Fc(int a,int b,int c,int d) {return bc[c][d]+bc[a-1][b-1]-bc[c][b-1]-bc[a-1][d];}
		pt.Wl(ans);
	}
}

public class Pt{
	private StringBuilder sb=new StringBuilder();
	public void W(int s){sb.Append(s);}
	public void W(long s){sb.Append(s);}
	public void W(double s){sb.Append(s);}
	public void W(decimal s){sb.Append(s);}
	public void W(string s){sb.Append(s);}
	public void W(object s){sb.Append(s);}
	public void W(string f,int s){sb.Append(s.ToString(f));}
	public void W(string f,long s){sb.Append(s.ToString(f));}
	public void W(string f,double s){sb.Append(s.ToString(f));}
	public void W(string f,decimal s){sb.Append(s.ToString(f));}
	public void Wl(int s){sb.Append(s).Append(Environment.NewLine);}
	public void Wl(long s){sb.Append(s).Append(Environment.NewLine);}
	public void Wl(double s){sb.Append(s).Append(Environment.NewLine);}
	public void Wl(decimal s){sb.Append(s).Append(Environment.NewLine);}
	public void Wl(string s){sb.Append(s).Append(Environment.NewLine);}
	public void Wl(object s){sb.Append(s).Append(Environment.NewLine);}
	public void Wl(string f,int s){sb.Append(s.ToString(f)).Append(Environment.NewLine);}
	public void Wl(string f,long s){sb.Append(s.ToString(f)).Append(Environment.NewLine);}
	public void Wl(string f,double s){sb.Append(s.ToString(f)).Append(Environment.NewLine);}
	public void Wl(string f,decimal s){sb.Append(s.ToString(f)).Append(Environment.NewLine);}
	public void Wl(int[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);}
	public void Wl(long[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);}
	public void Wl(double[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);}
	public void Wl(string[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);}
	public void Wl(object[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);}
	public void Wl(){sb.Append(Environment.NewLine);}
	public void Sm(){Console.Write(sb);}
}
public class Sc{
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	protected virtual string Rl(){return Console.ReadLine();}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	protected virtual string[] Sp(string st){return st.Split();}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	private T Ct<T>(string s){return (T)Convert.ChangeType(s,typeof(T));}
	public virtual int I{get{return int.Parse(Rl());}}
	public virtual long L{get{return long.Parse(Rl());}}
	public virtual double D{get{return double.Parse(Rl());}}
	public virtual string S{get{return Rl();}}
	public int[] Ia{get{return Array.ConvertAll(Sp(Rl()),int.Parse);}}
	public long[] La{get{return Array.ConvertAll(Sp(Rl()),long.Parse);}}
	public double[] Da{get{return Array.ConvertAll(Sp(Rl()),double.Parse);}}
	public string[] Sa{get{return Sp(Rl());}}
	public object[] Oa{get{return Sp(Rl());}}
	public int[] Ia2{get{return Array.ConvertAll(Sp("0 "+Rl()+" 0"),int.Parse);}}
	public int[] Ia3(string a,string b){return Array.ConvertAll(Sp(a+Rl()+b),int.Parse);}
	public int[] Ia3(int a){return Array.ConvertAll(Sp(Rl()+" "+a.ToString()),int.Parse);}
	public long[] La2{get{return Array.ConvertAll(Sp("0 "+Rl()+" 0"),long.Parse);}}
	public long[] La3(string a,string b){return Array.ConvertAll(Sp(a+Rl()+b),long.Parse);}
	public long[] La3(int a){return Array.ConvertAll(Sp(Rl()+" "+a.ToString()),long.Parse);}
	public double[] Da2{get{return Array.ConvertAll(Sp("0 "+Rl()+" 0"),double.Parse);}}
	public double[] Da3(string a,string b){return Array.ConvertAll(Sp(a+Rl()+b),double.Parse);}
	public T[] Arr<T>(int n,Func<T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f();}return a;}
	public T[] Arr<T>(int n,Func<int,T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i);}return a;}
	public T[] Arr<T>(int n,Func<string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(Sp(Rl()));}return a;}
	public T[] Arr<T>(int n,Func<int,string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i,Sp(Rl()));}return a;}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T) Tp2<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T,T) Tp3<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]),Ct<T>(s[2]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T,T,T) Tp4<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]),Ct<T>(s[2]),Ct<T>(s[3]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T,T,T,T) Tp5<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]),Ct<T>(s[2]),Ct<T>(s[3]),Ct<T>(s[4]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T,T,T,T,T) Tp6<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]),Ct<T>(s[2]),Ct<T>(s[3]),Ct<T>(s[4]),Ct<T>(s[5]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T1,T2) Tp2<T1,T2>(){var s=Sp(Rl());return (Ct<T1>(s[0]),Ct<T2>(s[1]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T1,T1,T2) Tp3<T1,T2>(){var s=Sp(Rl());return (Ct<T1>(s[0]),Ct<T1>(s[1]),Ct<T2>(s[2]));}
}
public class Scs:Sc{
	private StreamReader sr;
	public Scs(string t){sr=new StreamReader(t);}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	protected override string Rl(){return sr.ReadLine();}
}
public class Sc2:Sc{
	private string[] sps=new string[]{" ","　","\t"};
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	protected override string[] Sp(string st){return st.Split(sps,StringSplitOptions.RemoveEmptyEntries);}
	public override int I{get{return int.Parse(Sp(Rl())[0]);}}
	public override long L{get{return long.Parse(Sp(Rl())[0]);}}
	public override double D{get{return double.Parse(Sp(Rl())[0]);}}
	public override string S{get{return Sp(Rl())[0];}}
}
public class Scs2:Sc2{
	private StreamReader sr;
	public Scs2(string t){sr=new StreamReader(t);}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	protected override string Rl(){return sr.ReadLine();}
}
public class Sct:Sc{
	private List<string> li=new List<string>();
	private int l=0;
	public void Add(int s){li.Add(s.ToString());}
	public void Add(long s){li.Add(s.ToString());}
	public void Add(double s){li.Add(s.ToString());}
	public void Add(string s){li.Add(s.ToString());}
	public void Add(object s){li.Add(s.ToString());}
	public void Add(int[] s){li.Add(string.Join(" ",s));}
	public void Add(long[] s){li.Add(string.Join(" ",s));}
	public void Add(double[] s){li.Add(string.Join(" ",s));}
	public void Add(string[] s){li.Add(string.Join(" ",s));}
	public void Add(object[] s){li.Add(string.Join(" ",s));}
	protected override string Rl(){return li[l++];}
	public void Clear(){li.Clear();l=0;}
}