#include "race.h"
#include <bits/stdc++.h>
using namespace std;
const int maxn = 200005;
vector <pair <int, long long> > v[maxn];
long long dist[maxn];
int koraci[maxn];
int ans = 1e9;
void dfs2 (int x, int p){
for (int i = 0; i < v[x].size(); i++){
int y = v[x][i].first;
int d = v[x][i].second;
if (y != p){
dist[y] = dist[x] + d;
koraci[y] = koraci[x] + 1;
dfs2(y, x);
}
}
}
int best_path (int n, int k, int h[maxn][2], int l[maxn]){
for (int i = 0; i < n - 1; i++){
v[h[i][0]].push_back({h[i][1], l[i]});
v[h[i][1]].push_back({h[i][0], l[i]});
}
for (int i = 0; i < n; i++){
dist[i] = 0, koraci[i] = 0;
dfs2(i, i);
for (int j = 0; j < n; j++){
if (dist[j] == k) ans = min(ans, koraci[j]);
}
}
if (ans == 1e9) return -1;
else return ans;
}
/*
int main (void){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int n, k, h[maxn][2], l[maxn];
cin >> n >> k;
for (int i = 0; i < n - 1; i++) cin >> h[i][0] >> h[i][1] >> l[i];
cout << best_path(n, k, h, l) << endl;
return 0;
}*/
