#include<bits/stdc++.h>
#include "crocodile.h"
using namespace std;
typedef long long ll;
const int MAX = 2e6 + 15;
const ll INF = 5e18 + 50;
#define fr first
#define sc second
ll dp[MAX], ans;
bool ex[MAX];
vector<ll> adj[MAX], w[MAX];
void calcdp(int u, int p){
if(adj[u].size() == 1){ dp[u] = 0; return; }
ll mn1 = INF, mn2 = INF;
for(int i = 0; i < (int) adj[u].size(); i++){
ll v = adj[u][i], c = w[u][i];
if(v == p) continue;
calcdp(v, u);
ll cur = dp[v] + c;
if(cur < mn1){ swap(mn1, mn2); swap(mn1, cur); }
else if(cur < mn2){ swap(mn2, cur); }
}
dp[u] = mn2;
}
int travel_plan(int n, int m, int R[][2], int L[], int k, int P[]){
assert(m == n - 1);
for(int i = 0; i < m; i++){
int u = R[i][0], v = R[i][1];
adj[u].push_back(v);
adj[v].push_back(u);
w[u].push_back(L[i]);
w[v].push_back(L[i]);
}
calcdp(0, -1);
return dp[0];
}
