#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <queue>
#include <string>
#include <map>
#include <set>
#include <stack>
#include <tuple>
#include <deque>
#include <array>
#include <numeric>
#include <bitset>
#include <iomanip>
#include <cassert>
#include <chrono>
#include <random>
#include <limits>
#include <iterator>
#include <functional>
#include <sstream>
#include <fstream>
#include <complex>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
using namespace std;

// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")

using ll = long long;
constexpr int INF = 1001001001;
// constexpr int mod = 1000000007;
constexpr int mod = 998244353;

template<class T>
inline bool chmax(T& x, T y){
    if(x < y){
        x = y;
        return true;
    }
    return false;
}
template<class T>
inline bool chmin(T& x, T y){
    if(x > y){
        x = y;
        return true;
    }
    return false;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N, K;
    cin >> N >> K;
    vector<vector<pair<int, int>>> g(N);
    for(int i = 1; i < N; ++i){
        int a, b, c;
        cin >> a >> b >> c;
        --a, --b;
        g[a].emplace_back(b, c);
        g[b].emplace_back(a, c);
    }

    vector<pair<int, int>> dat;
    vector<int> dist(N);
    int ans = 0;
    auto dfs = [&](auto&& self, int from = 0, int d = 0, int par = -1) -> int {
        int res = 0;
        dist[from] = d;
        for(auto& [to, cost] : g[from]){
            if(to == par)   continue;
            int cnt = self(self, to, d + cost, from);
            dat.emplace_back(cost * cnt, cost);
            res += cnt;
        }
        if(res == 0){
            ans += dist[from];
            res = 1;
        }
        return res;
    };
    dfs(dfs);

    sort(rbegin(dat), rend(dat));
    vector dp(N, vector<int>(K + 1));
    for(int i = 0; i < N - 1; ++i){
        auto& [val, cost] = dat[i];
        for(int j = 0; j <= K; ++j){
            chmax(dp[i + 1][j], dp[i][j]);
            if(j + cost <= K)   chmax(dp[i + 1][j + cost], dp[i][j] + val);
        }
    }

    cout << ans + *max_element(begin(dp[N - 1]), end(dp[N - 1])) << endl;

    return 0;
}