#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 1000000007;
// constexpr int MOD = 998244353;
constexpr int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
constexpr int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

template <typename CostType>
struct Edge {
  int src, dst; CostType cost;
  Edge(int src, int dst, CostType cost = 0) : src(src), dst(dst), cost(cost) {}
  inline bool operator<(const Edge &x) const {
    return cost != x.cost ? cost < x.cost : dst != x.dst ? dst < x.dst : src < x.src;
  }
  inline bool operator<=(const Edge &x) const { return !(x < *this); }
  inline bool operator>(const Edge &x) const { return x < *this; }
  inline bool operator>=(const Edge &x) const { return !(*this < x); }
};

int main() {
  int n, k; cin >> n >> k;
  vector<vector<Edge<int>>> graph(n);
  REP(_, n - 1) {
    int a, b, c; cin >> a >> b >> c; --a; --b;
    graph[a].emplace_back(a, b, c);
    graph[b].emplace_back(b, a, c);
  }
  vector<pair<int, int>> edge;
  auto f = [&](auto &&f, int par, int ver) -> int {
    int leaf = 0;
    for (const Edge<int> &e : graph[ver]) {
      if (e.dst != par) {
        int child = f(f, ver, e.dst);
        edge.emplace_back(e.cost, child);
        leaf += child;
      }
    }
    return leaf == 0 ? 1 : leaf;
  };
  f(f, -1, 0);
  vector<int> dp(k + 1, -INF);
  dp[0] = 0;
  for (auto [c, leaf] : edge) {
    for (int i = k; i >= 0; --i) {
      if (i + c <= k) chmax(dp[i + c], dp[i] + c * leaf * 2);
      dp[i] += c * leaf;
    }
  }
  cout << *max_element(ALL(dp)) << '\n';
  return 0;
}