#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPR(i, n) for (int i = n - 1; i >= 0; --i)
#define FOR(i, m, n) for (int i = m; i < n; ++i)
#define FORR(i, m, n) for (int i = m; i >= n; --i)
#define ALL(v) (v).begin(),(v).end()
#define ALLR(v) (v).rbegin(),(v).rend()
#define fi first
#define se second
#define PB push_back
#define EB emplace_back
using P = pair<ll, ll>;
template<typename T> using PQ = priority_queue<T>;
template<typename T> using QP = priority_queue<T,vector<T>,greater<T>>;
template<typename T>void debug(const T &v,ll h,ll w){for(ll i=0;i<h;i++){for(ll j=0;j<w;j++)cout<<v[i][j]<<" \n"[j==w-1];}};
template<typename T>void debug(const T &v,ll n){for(ll i=0;i<n;i++)cout<<v[i]<<" \n"[i==n-1];};
template<typename T>void debug(const vector<T>&v){debug(v,v.size());}
template<typename T>void debug(const vector<vector<T>>&v){for(auto &vv:v)debug(vv,vv.size());}
template<typename T>void debug(stack<T> st){while(!st.empty()){cout<<st.top()<<" ";st.pop();}cout<<endl;}
template<typename T>void debug(queue<T> st){while(!st.empty()){cout<<st.front()<<" ";st.pop();}cout<<endl;}
template<typename T>void debug(deque<T> st){while(!st.empty()){cout<<st.front()<<" ";st.pop_front();}cout<<endl;}
template<typename T>void debug(PQ<T> st){while(!st.empty()){cout<<st.top()<<" ";st.pop();}cout<<endl;}
template<typename T>void debug(QP<T> st){while(!st.empty()){cout<<st.top()<<" ";st.pop();}cout<<endl;}
template<typename T>void debug(const set<T>&v){for(auto z:v)cout<<z<<" ";cout<<endl;}
template<typename T>void debug(const multiset<T>&v){for(auto z:v)cout<<z<<" ";cout<<endl;}
template<typename T,size_t size>void debug(const array<T, size> &a){for(auto z:a)cout<<z<<" ";cout<<endl;}
template<typename T,typename V>void debug(const map<T,V>&v){for(auto z:v)cout<<"["<<z.first<<"]="<<z.second<<",";cout<<endl;}
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
int popcount(ll x){return __builtin_popcountll(x);};
int poplow(ll x){return __builtin_ctzll(x);};
int pophigh(ll x){return 63 - __builtin_clzll(x);};
const ll INF=1LL<<60;
const int inf=(1<<30)-1;
// const int mod=1e9+7;
const int mod=998244353;
int dx[8]={1,0,-1,0,-1,-1,1,1};
int dy[8]={0,1,0,-1,-1,1,-1,1};

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n,k;cin >> n >> k;
    vector<vector<pair<int,int>>> e(n);
    vector<int> h(n);
    REP(i,n-1){
        int a,b,c;cin >> a >> b >> c;
        a--,b--;
        e[a].PB({b,c});
        e[b].PB({a,c});
        h[a]++,h[b]++;
    }
    vector<int> d(n),x(n);
    vector<int> w,v;
    auto dfs=[&](auto &&dfs,int cur,int pre=-1)->void{
        for(auto to:e[cur]){
            if(to.fi==pre) continue;
            d[to.fi]=d[cur]+to.se;
            dfs(dfs,to.fi,cur);
            x[cur]+=x[to.fi];
            w.PB(to.se);
            v.PB(to.se*x[to.fi]);
        }
        if(h[cur]==1) x[cur]++;
    };
    dfs(dfs,0);
    vector<vector<int>> dp(n,vector<int>(k+1,-1));
    dp[0][0]=0;
    REP(i,n-1){
        REP(j,k+1){
            if(dp[i][j]==-1) continue;
            chmax(dp[i+1][j],dp[i][j]);
            if(j+w[i]<=k) chmax(dp[i+1][j+w[i]],dp[i][j]+v[i]);
        }
    }
    int ans=0;
    REP(i,k+1) chmax(ans,dp[n-1][i]);
    REP(i,n) if(h[i]==1) ans+=d[i];
    cout << ans << endl;
}