#include "race.h"
#include<bits/stdc++.h>
using namespace std;
#define INIT ios_base :: sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define mp make_pair
#define pb push_back
#define ft first
#define sc second
#define ll long long
#define pii pair<int, int>
#define count_bits __builtin_popcount
int n, k;
vector<pii> g[1010];
bool v[1010];
int dfs(int s, int l, int h){
int res=1e9;
if(l>k){
return res;
}
if(l==k){
return h;
}
v[s]=true;
for(pii pr:g[s]){
int u=pr.ft, d=pr.sc;
if(!v[u]){
res=min(dfs(u, l+d, h+1), res);
}
}
v[s]=false;
return res;
}
int best_path(int N, int K, int H[][2], int L[])
{
n=N; k=K;
int res=1e9;
for(int i=0; i<n; i++){
int u=H[i][0]+1, v=H[i][1]+1, d=L[i];
g[u].pb({v, d}); g[v].pb({u, d});
}
for(int i=1; i<=n;i++){
res=min(res, dfs(i, 0, 1));
}
if(res==(1e9)){
return -1;
}
return res-1;
}
