#include <bits/stdc++.h>
#include "race.h"
using namespace std;
typedef long long ll;
const int max_n = 200000;
vector<pair<int,int>> g[max_n];
bool vis[max_n];
int ans = INT_MAX;
void dfs(int u, int k, ll dist = 0, int length = 0)
{
if (dist == k)
{
ans = min(ans, length);
return;
}
if (dist > k || length >= ans)
return;
vis[u] = true;
for (auto [v, l] : g[u])
if (!vis[v])
dfs(v, k, dist + l, length + 1);
}
int best_path(int N, int K, int H[][2], int L[])
{
for (int i = 0; i < N - 1; i++)
{
g[H[i][0]].push_back({H[i][1], L[i]});
g[H[i][1]].push_back({H[i][0], L[i]});
}
for (int i = 0; i < N; i++)
{
memset(vis, false, sizeof(vis));
dfs(i, K);
}
return (ans == INT_MAX ? -1 : ans);
}
