import java.io.*;
import java.util.*;

public class Main {
    static ArrayList<ArrayList<Path>> graph = new ArrayList<>();
    static ArrayList<Path> paths = new ArrayList<>();
    static int total = 0;
    static int[][] dp;
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int k = sc.nextInt();
        for (int i = 0; i < n; i++) {
            graph.add(new ArrayList<>());
        }
        for (int i = 0; i < n - 1; i++) {
            int a = sc.nextInt() - 1;
            int b = sc.nextInt() - 1;
            int c = sc.nextInt();
            graph.get(a).add(new Path(b, c));
            graph.get(b).add(new Path(a, c));
        }
        getChildren(0, 0, 0);
        dp = new int[n - 1][k + 1];
        System.out.println(dfw(n - 2, k) + total);
    }
    
    static int dfw(int idx, int cost) {
        if (cost < 0) {
            return Integer.MIN_VALUE;
        }
        if (idx < 0) {
            return 0;
        }
        if (dp[idx][cost] == 0) {
            Path p = paths.get(idx);
            dp[idx][cost] = Math.max(dfw(idx - 1, cost), dfw(idx - 1, cost - p.value) + p.count * p.value);
        }
        return dp[idx][cost];
    }
    
    static int getChildren(int idx, int parent, int value) {
        int sum = 0;
        for (Path p : graph.get(idx)) {
            if (p.idx == parent) {
                continue;
            }
            p.count = getChildren(p.idx, idx, value + p.value);
            sum += p.count;
            paths.add(p);
        }
        if (sum == 0) {
            total += value;
            sum++;
        }
        return sum;
    }
    
    static class Path {
        int idx;
        int value;
        int count;
        
        public Path(int idx, int value) {
            this.idx = idx;
            this.value = value;
        }
    }
}

class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}