#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <iterator>
#include <cassert>
#include <numeric>
#include <functional>
#include <ctime>
#pragma warning(disable:4996) 

//#define ATCODER
#ifdef ATCODER
#include <atcoder/all>
#endif

typedef long long ll;
typedef unsigned long long ull;
#define LINF  9223300000000000000
#define LINF2 1223300000000000000
#define LINF3 1000000000000
#define INF 2140000000
const long long MOD = 1000000007;
//const long long MOD = 998244353;

using namespace std;
#ifdef ATCODER
using namespace atcoder;
#endif

vector<vector<pair<int,int>>> g;  // to,edge
vector<int> c;
vector<int> num0;
ll ans0;

int dfs(int par, int curr, ll dd)
{
    int sum = 0;
    for (int i = 0; i < (int)g[curr].size(); i++) {
        int ne=g[curr][i].first;
        int edge = g[curr][i].second;
        if (par == ne) continue;
        num0[edge] = dfs(curr, ne, dd+c[edge]);
        sum += num0[edge];
    }
    if (sum == 0) {
        ans0 += dd;
        sum++;
    }
    return sum;
}

void solve()
{
    int n, K;
    scanf("%d%d", &n, &K);
    c.resize(n - 1);
    g.resize(n); num0.resize(n - 1);
    for (int i = 0; i < n - 1; i++) {
        int a, b;
        scanf("%d%d%d", &a, &b, &c[i]); a--; b--;
        g[a].push_back(make_pair(b, i));
        g[b].push_back(make_pair(a, i));
    }
    int ret = dfs(-1, 0, 0);
    //assert(ret == n);

    vector<vector<ll>> dp(n, vector<ll>(K + 1, -LINF));
    dp[0][0] = 0;
    for (int i = 0; i < n - 1; i++) {
        for (int j = 0; j <= K; j++) {
            if (dp[i][j] < 0) continue;
            dp[i + 1][j] = max(dp[i + 1][j], dp[i][j]);
            int j2 = j + c[i];
            if (j2 <= K) {
                dp[i + 1][j2] = max(dp[i + 1][j2], dp[i][j] + (ll)c[i]*num0[i]);
            }
        }
    }

    ll ans = -LINF;
    for (int j = 0; j <= K; j++) {
        ans=max(ans, dp[n - 1][j]);
    }
    printf("%lld\n", ans+ans0);
    return;
}


int main()
{
#if 1
    solve();
#else
    int T, t;
    scanf("%d", &T);
    for (t = 0; t < T; t++) {
        //printf("Case #%d: ", t + 1);
        solve();
    }
#endif
    return 0;
}