#include <bits/stdc++.h>

using i32 = std::int32_t;
using u32 = std::uint32_t;
using i64 = std::int64_t;
using u64 = std::uint64_t;
using i128 = __int128_t;
using u128 = __uint128_t;
using isize = std::ptrdiff_t;
using usize = std::size_t;

class rep {
    struct Iter {
        usize itr;
        constexpr Iter(const usize pos) noexcept : itr(pos) {}
        constexpr void operator++() noexcept { ++itr; }
        constexpr bool operator!=(const Iter& other) const noexcept {
            return itr != other.itr;
        }
        constexpr usize operator*() const noexcept { return itr; }
    };
    const Iter first, last;

  public:
    explicit constexpr rep(const usize first, const usize last) noexcept
        : first(first), last(std::max(first, last)) {}
    constexpr Iter begin() const noexcept { return first; }
    constexpr Iter end() const noexcept { return last; }
};

class revrep {
    struct Iter {
        usize itr;
        constexpr Iter(const usize pos) noexcept : itr(pos) {}
        constexpr void operator++() noexcept { --itr; }
        constexpr bool operator!=(const Iter& other) const noexcept {
            return itr != other.itr;
        }
        constexpr usize operator*() const noexcept { return itr; }
    };
    const Iter first, last;

  public:
    explicit constexpr revrep(const usize first, const usize last) noexcept
        : first(last - 1), last(std::min(first, last) - 1) {}
    constexpr Iter begin() const noexcept { return first; }
    constexpr Iter end() const noexcept { return last; }
};

template <class T> bool setmax(T& lhs, const T& rhs) {
    if (lhs < rhs) {
        lhs = rhs;
        return true;
    }
    return false;
}

template <class F> struct RecLambda : private F {
    template <class G>
    explicit constexpr RecLambda(G&& g) : F(std::forward<G>(g)) {}
    template <class... Args>
    constexpr decltype(auto) operator()(Args&&... args) const {
        return F::operator()(*this, std::forward<Args>(args)...);
    }
};

template <class G> explicit RecLambda(G&&) -> RecLambda<std::decay_t<G>>;

template <class T> using Vec = std::vector<T>;

void D_main() {
    usize N;
    u32 K;
    std::cin >> N >> K;
    Vec<usize> A(N - 1), B(N - 1);
    Vec<u32> C(N - 1);
    Vec<Vec<std::pair<usize, u32>>> graph(N);
    for (const auto i : rep(0, N - 1)) {
        std::cin >> A[i] >> B[i] >> C[i];
        A[i] -= 1;
        B[i] -= 1;
        graph[A[i]].emplace_back(B[i], C[i]);
        graph[B[i]].emplace_back(A[i], C[i]);
    }
    Vec<usize> parent(N), subtree(N);
    u64 cur = 0;
    RecLambda(
        [&](auto&& dfs, const usize u, const usize p, const u64 d) -> void {
            parent[u] = p;
            for (const auto [v, c] : graph[u]) {
                if (v != p) {
                    dfs(v, u, d + c);
                    subtree[u] += subtree[v];
                }
            }
            if (subtree[u] == 0) {
                subtree[u] = 1;
                cur += d;
            }
        })(0, 0, 0);
    Vec<u64> dp(K + 1);
    for (const auto i : rep(0, N - 1)) {
        if (parent[B[i]] == A[i]) {
            std::swap(A[i], B[i]);
        }
        const u64 get = (u64)subtree[A[i]] * C[i];
        const u64 cost = C[i];
        for (const auto j : revrep(cost, K + 1)) {
            setmax(dp[j], dp[j - cost] + get);
        }
    }
    std::cout << cur + dp[K] << '\n';
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    D_main();
    return 0;
}