#include<iostream>
#include<set>
#include<map>
#include<vector>
#include<queue>
#include<algorithm>
#include<tuple>
using namespace std;
typedef pair<int,int> P;
typedef long long ll;

struct edge{
    int from;
    int to;
    ll cost;
    int id;
    edge(int from_,int to_,ll cost_,int id_):from(from_),to(to_),cost(cost_),id(id_){};
};

int main(){
    int N,K;
    cin>>N>>K;
    vector<vector<edge>> G(N);

    vector<edge> edges;

    for(int i=0;i<N-1;i++){
        int a,b;
        ll c;
        cin>>a>>b>>c;
        a--;b--;
        //edges[i]=edge(a,b,c,i);
        //edges[i]=(edge){a,b,c,i};
        edges.emplace_back(a,b,c,i);


        G[a].emplace_back(a,b,c,i);
        G[b].emplace_back(b,a,c,i);
    }

    vector<P> dp(N);

    //部分木の葉の数を数える
    auto dfs=[&](auto f,int now,int pre,int edgeid)->P{
        bool flag=true;
        int res=0;

        for(edge e:G[now]){
            if(e.to==pre) continue;
            flag=false;
            res+=f(f,e.to,now,e.id).first; //e.toの部分木にある葉の数
        }

        if(flag){
            res+=1; //now自身が葉
        }
        return dp[now]=make_pair(res,edgeid);

    };

   
    for(edge e:G[0]){
         dfs(dfs,e.to,0,e.id);
    }

    //cout<<"te"<<endl;

    sort(dp.begin(),dp.end(),[&](const P&lhs, const P&rhs){
        return 1LL*lhs.first*(edges[lhs.second].cost) > 1LL*rhs.first*(edges[rhs.second].cost);
    });

    //cout<<"te"<<endl;

    ll add=0;
    ll len=0;
    for(int i=0;i<N;i++){
        if(len+edges[dp[i].second].cost<=K){
            add += 1LL*dp[i].first*edges[dp[i].second].cost;
            len+=edges[dp[i].second].cost;

            //cout<<"edgeid="<<dp[i].second<<endl;
            //cout<<"cnt="<<dp[i].first<<endl;
        }
    }


    //cout<<"te"<<endl;

    ll tot=0;

    auto dfs2=[&](auto f,int now,int pre,ll depth)->void{
        bool flag=true;
        int res=0;
        for(edge e:G[now]){
            if(e.to==pre) continue;
            flag=false;
            f(f,e.to,now,depth+e.cost);
        }

        if(flag){
            //nowが根の場合のみ　足される
            tot+=depth;
        }
        return;
    };

    dfs2(dfs2,0,-1,0);

    /*
     cout<<"te"<<endl;
    cout<<"tot="<<tot<<endl;
    */

    ll ans=add+tot;

    cout<<ans<<endl;


}