#include <bits/stdc++.h>
using namespace std;
#define mp make_pair
#define pb push_back
#define pii pair<int,int>
#define fi first
#define se second
#include "race.h"
const int maxn=1005;
vector<vector<pii>> adj(maxn);
vector<int> w(maxn),d(maxn),vis(maxn);
void dfs(int u,int p,int dep,int from){
if(vis[u]) return;
w[u]=p; d[u]=dep; vis[u]=1;
for(auto&v:adj[u]){
if(!vis[v.fi]&& v.fi!=from)
dfs(v.fi,p+v.se,dep+1,u);
}
}
int best_path(int n, int k, int H[][2], int L[])
{
for(int i=0;i<n-1;i++){
adj[H[i][0]].pb(mp(H[i][1],L[i]));
adj[H[i][1]].pb(mp(H[i][0],L[i]));
}
int ans=INT_MAX;
for(int i=0;i<n;i++){
for(int j=0;j<n;j++){
d[j]=-1;
w[j]=-1;
vis[j]=0;
}
dfs(i,0,0,i);
for(int j=0;j<n;j++){
if(w[j]==k) ans=min(ans,d[j]);
}
}
if(ans==INT_MAX) return -1;
else return ans;
}
