#include <iostream>
#include <vector>
#include <queue>
using namespace std;
using ll = long long;
#define rep(i,n) for(int i=0; i<(n); i++)

struct Edge{ int to, d; };

int N, K;
vector<vector<Edge>> E;
vector<int> I;
vector<int> P;
vector<int> D;
vector<int> Z;

int main(){
  scanf("%d%d",&N,&K);
  E.resize(N);
  rep(i,N-1){
    int u,v,d; scanf("%d%d%d",&u,&v,&d); u--; v--;
    E[u].push_back({v,d});
    E[v].push_back({u,d});
  }


  P.assign(N,-1);
  D.assign(N,0);
  Z.assign(N,1);
  queue<int> Q;
  Q.push(0);
  while(Q.size()){
    int p = Q.front(); Q.pop();
    I.push_back(p);
    for(Edge e : E[p]) if(P[p] != e.to){
      P[e.to] = p;
      D[e.to] = e.d;
      Q.push(e.to);
      Z[p] = 0;
    }
  }
  for(int i=N-1; i>=1; i--){ int p=I[i]; Z[P[p]]+=Z[p]; }
  
  ll ans = 0;
  rep(i,N) ans += (ll)Z[i] * D[i];
  vector<ll> dp(K+1,0);
  rep(i,N){
    vector<ll> tmp = dp;
    for(int k=D[i]; k<=K; k++) tmp[k] = max(tmp[k],dp[k-D[i]]+Z[i]*D[i]);
    dp = move(tmp);
  }

  printf("%lld\n",ans+dp[K]);

  return 0;
}