#pragma region Macros
#include <bits/stdc++.h>
#define rep(i, n) for(int(i) = 0; (i) < (n); (i)++)
#define FOR(i, m, n) for(int(i) = (m); (i) < (n); (i)++)
#define ALL(v) (v).begin(), (v).end()
#define LLA(v) (v).rbegin(), (v).rend()
#define SZ(v) (int)(v).size()
#define INT(...)                                                               \
    int __VA_ARGS__;                                                           \
    read(__VA_ARGS__)
#define LL(...)                                                                \
    ll __VA_ARGS__;                                                            \
    read(__VA_ARGS__)
#define DOUBLE(...)                                                            \
    double __VA_ARGS__;                                                        \
    read(__VA_ARGS__)
#define CHAR(...)                                                              \
    char __VA_ARGS__;                                                          \
    read(__VA_ARGS__)
#define STRING(...)                                                            \
    string __VA_ARGS__;                                                        \
    read(__VA_ARGS__)
#define VEC(type, name, size)                                                  \
    vector<type> name(size);                                                   \
    read(name)
#define VEC2(type, name, height, width)                                        \
    vector<vector<type>> name(height, vector<type>(width));                    \
    read(name)
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using Graph = vector<vector<int>>;
template <typename T> struct edge {
    int from, to;
    T cost;
    edge(int f, int t, T c) : from(f), to(t), cost(c) {}
    edge() = default;
};
template <typename T> using WGraph = vector<vector<edge<T>>>;
const int INF = 1 << 30;
const ll LINF = 1LL << 60;
const int MOD = 1e9 + 7;
const char newl = '\n';
template <class T> inline vector<T> make_vec(size_t a, T val) {
    return vector<T>(a, val);
}
template <class... Ts> inline auto make_vec(size_t a, Ts... ts) {
    return vector<decltype(make_vec(ts...))>(a, make_vec(ts...));
}
void read() {}
template <class T> inline void read(T &a) { cin >> a; }
template <class T, class S> inline void read(pair<T, S> &p) {
    read(p.first), read(p.second);
}
template <class T> inline void read(vector<T> &v) {
    for(auto &&a : v)
        read(a);
}
template <class Head, class... Tail>
inline void read(Head &head, Tail &...tail) {
    read(head), read(tail...);
}
template <class T> void write(const T &a) { cout << a << '\n'; }
template <class T> void write(const vector<T> &a) {
    for(int i = 0; i < a.size(); i++)
        cout << a[i] << (i + 1 == a.size() ? '\n' : ' ');
}
template <class Head, class... Tail>
void write(const Head &head, const Tail &...tail) {
    cout << head << ' ';
    write(tail...);
}
template <class T> void writel(const T &a) { cout << a << '\n'; }
template <class T> void writel(const vector<T> &a) {
    for(int i = 0; i < a.size(); i++)
        cout << a[i] << '\n';
}
template <class Head, class... Tail>
void writel(const Head &head, const Tail &...tail) {
    cout << head << '\n';
    write(tail...);
}
template <class T> auto sum(const vector<T> &a) {
    return accumulate(ALL(a), T(0));
}
template <class T> auto min(const vector<T> &a) { return *min_element(ALL(a)); }
template <class T> auto max(const vector<T> &a) { return *max_element(ALL(a)); }
template <class T> inline void chmax(T &a, T b) { (a < b ? a = b : a); }
template <class T> inline void chmin(T &a, T b) { (a > b ? a = b : a); }
struct IO {
    IO() {
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
        cout << fixed << setprecision(10);
    }
} io;
#pragma endregion

int main() {
    INT(n, k);
    WGraph<ll> g(n);
    vector<edge<ll>> edges(n - 1);
    rep(i, n - 1) {
        INT(a, b, c);
        a--, b--;
        g[a].emplace_back(a, b, c);
        g[b].emplace_back(b, a, c);
        edges[i] = edge<ll>(a, b, c);
    }
    auto sz = make_vec(n, -1);
    auto depth = make_vec(n, -1);
    ll base = 0;
    auto f = [&](auto &&f, int v, int p) -> int {
        int ret = 0;
        if(sz[v] != -1)
            return sz[v];
        if(g[v].size() == 1 && p != -1) {
            return sz[v] = 1;
        }
        for(auto e : g[v]) {
            if(e.to == p)
                continue;
            ret += f(f, e.to, v);
        }
        return sz[v] = ret;
    };
    auto rec = [&](auto &&rec, int v, int p, ll r) -> void {
        if(g[v].size() == 1 && p != -1) {
            base += r;
            return;
        }
        for(auto e : g[v]) {
            if(e.to == p)
                continue;
            rec(rec, e.to, v, r + e.cost);
        }
    };
    f(f, 0, -1);
    rec(rec, 0, -1, 0LL);
    auto dp = make_vec(n, k + 1, -1LL);
    auto cost = make_vec(n - 1, 0LL);
    auto value = make_vec(n - 1, 0LL);
    dp[0][0] = 0;
    rep(i, n - 1) {
        auto e = edges[i];
        cost[i] = e.cost;
        value[i] = e.cost * (min(sz[e.to], sz[e.from]));
    }
    for(int i = 0; i < n - 1; i++) {
        for(int j = 0; j <= k; j++) {
            if(dp[i][j] == -1)
                continue;
            chmax(dp[i + 1][j], dp[i][j]);
            if(j + cost[i] <= k)
                chmax(dp[i + 1][j + cost[i]], dp[i][j] + value[i]);
        }
    }
    ll res = -1;
    rep(i, k + 1) { chmax(res, dp[n - 1][i]); }
    write(base + res);
}