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

public class Main {
    static ArrayList<HashMap<Integer, Integer>> graph = new ArrayList<>();
    static Node[] nodes;
    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 HashMap<>());
        }
        nodes = new Node[n - 1];
        for (int i = 0; i < n - 1; i++) {
            nodes[i] = new Node(sc.nextInt() - 1, sc.nextInt() - 1, sc.nextInt());
            graph.get(nodes[i].left).put(nodes[i].right, i);
            graph.get(nodes[i].right).put(nodes[i].left, i);
        }
        setCounts(0, 0);
        dp = new int[n - 1][k + 1];
        System.out.println(dfw(n - 2, k));
    }
    
    static int setCounts(int idx, int p) {
        int count = 0;
        for (int x : graph.get(idx).keySet()) {
            if (x == p) {
                continue;
            }
            count += setCounts(x, idx);
        }
        if (count == 0) {
            count = 1;
        }
        if (idx != p) {
            nodes[graph.get(idx).get(p)].count = count;
        }
        return count;
    }
    
    static int dfw(int idx, int v) {
        if (v < 0) {
            return Integer.MIN_VALUE;
        }
        if (idx < 0) {
            return 0;
        }
        if (dp[idx][v] == 0) {
            dp[idx][v] = Math.max(dfw(idx - 1, v) + nodes[idx].getSum(), dfw(idx - 1, v - nodes[idx].score) + nodes[idx].getSum() * 2);
        }
        return dp[idx][v];
    }
    
    static class Node {
        int left;
        int right;
        int score;
        int count;
        
        public Node(int left, int right, int score) {
            this.left = left;
            this.right = right;
            this.score = score;
        }
        
        public int getSum() {
            return score * count;
        }
        
        public String toString() {
            return score + ":" + count;
        }
    }
}

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 double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}