#include<bits/stdc++.h>
using namespace std;

using ll=long long;
using pii=pair<int,int>;
#define pb push_back
#define all(a) a.begin(),a.end()
#define sz(a) ((int)a.size())

const int N=2005;
int n,m,a[N],dis[N],par[N],d[N];
vector<pii> adj[N];
bool vis[N];

void dfs(int u, int fa){
    par[u]=fa;
    for(auto [v,w]: adj[u]) if(v!=fa) dis[v]=dis[u]+w,d[v]=w,dfs(v,u);
}

signed main(){
    cin >> n >> m;
    for(int i=0; i<n-1; ++i){
        int u,v,w; cin >> u >> v >> w; u--,v--;
        adj[u].pb({v,w}),adj[v].pb({u,w});
    }
    for(int i=0; i<n; ++i) cin >> a[i];
    vector<ll> res;
    for(int i=0; i<n; ++i){
        dis[i]=0;
        dfs(i,-1);
        for(int j=0; j<n; ++j) vis[j]=0;
        vector<int> ord(n);
        iota(all(ord),0);
        sort(all(ord),[&](int u, int v){return dis[u]>dis[v];});
        vis[i]=1;
        for(int u: ord){
            ll tot=0;
            for(int cur=u; !vis[cur]; cur=par[cur]){
                vis[cur]=1;
                tot+=d[cur];
            }
            if(tot) res.pb(tot*a[i]);
        }
    }
    sort(all(res)),reverse(all(res));
    ll tot=0;
    for(int i=0; i<m&&i<sz(res); ++i) tot+=res[i];
    cout << tot << "\n";
}