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

public class Main {
    static int[] lengths;
    static long[] counts;
    static long[][] dp;
    static ArrayList<HashMap<Integer, Integer>> graph = new ArrayList<>();
    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<>());
        }
        lengths = new int[n - 1];
        counts = new long[n - 1];
        for (int i = 0; i < n - 1; i++) {
            int a = sc.nextInt() - 1;
            int b = sc.nextInt() - 1;
            lengths[i] = sc.nextInt();
            graph.get(a).put(b, i);
            graph.get(b).put(a, i);
        }
        getCount(0, 0);
        dp = new long[n - 1][k + 1];
        for (long[] arr : dp) {
            Arrays.fill(arr, -1);
        }
        System.out.println(dfw(n - 2, k));
    }
    
    static long getCount(int idx, int p) {
        long count = 0;
        if (graph.get(idx).size() == 1) {
            count++;
        }
        for (int x : graph.get(idx).keySet()) {
            if (x == p) {
                continue;
            }
            counts[graph.get(idx).get(x)] = getCount(x, idx);
            count += counts[graph.get(idx).get(x)];
        }
        return count;
    }
    
    static long dfw(int idx, int v) {
        if (v < 0) {
            return Long.MIN_VALUE;
        }
        if (idx < 0) {
            return 0;
        }
        if (dp[idx][v] < 0) {
            dp[idx][v] = Math.max(dfw(idx - 1, v) + lengths[idx] * counts[idx], dfw(idx - 1, v - lengths[idx]) + lengths[idx] * counts[idx] * 2);
        }
        return dp[idx][v];
    }
}
class Utilities {
    static String arrayToLineString(Object[] arr) {
        return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n"));
    }
    
    static String arrayToLineString(int[] arr) {
        return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new));
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    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 int[] nextIntArray() throws Exception {
        return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}