import java.io.*;
import java.util.*;
import java.util.function.*;
import java.util.stream.*;

public class Main {
    static long[] dp;
    static List<Speech> speeches = new ArrayList<>();
    static int wake;
    static int sleep;
    static TreeMap<Integer, Integer> compress = new TreeMap<>();
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        wake = sc.nextInt();
        sleep = sc.nextInt();
        for (int i = 0; i < n; i++) {
            Speech current = new Speech(sc.nextInt(), sc.nextInt(), sc.nextInt());
            if (current.length() <= wake) {
                speeches.add(current);
            }
        }
        Collections.sort(speeches);
        for (int i = 0; i <  speeches.size(); i++) {
            compress.put(speeches.get(i).end, i);
        }
        compress.put(Integer.MIN_VALUE, -1);
        dp = new long[speeches.size()];
        Arrays.fill(dp, -1);
        System.out.println(dfw(speeches.size() - 1));
    }
    
    static long dfw(int idx) {
        if (idx < 0) {
            return 0;
        }
        if (dp[idx] < 0) {
            dp[idx] = Math.max(dfw(idx - 1), dfw(compress.floorEntry(speeches.get(idx).start - sleep).getValue()) + speeches.get(idx).value);
        }
        return dp[idx];
    }
    
    static class Speech implements Comparable<Speech> {
        int start;
        int end;
        int value;
        
        public Speech(int start, int end, int value) {
            this.start = start;
            this.end = end;
            this.value = value;
        }
        
        public int compareTo(Speech another) {
            return end - another.end;
        }
        
        public int length() {
            return end - start;
        }
    }
}
class Scanner {
    BufferedReader br;
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() {
        try {
            br = new BufferedReader(new InputStreamReader(System.in));
        } catch (Exception e) {
            
        }
    }
    
    public int nextInt() {
        return Integer.parseInt(next());
    }
    
    public long nextLong() {
        return Long.parseLong(next());
    }
    
    public double nextDouble() {
        return Double.parseDouble(next());
    }
    
    public String next() {
        try {
            while (!st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            return st.nextToken();
        }
    }
    
}