#define F first
#define S second
#define rep(i,a,b) for(int i=a;!(a==b&&i!=b)&&((i<=b&&b>=a)||(i>=b&&a>=b));i+=(a<=b?1:-1))
#define pb push_back
#define Fbitl __builtin_ffs
#define bit1 __builtin_popcount
//#include <bits/stdc++.h>
#include <iostream>
#include <math.h>
#include <algorithm>
#include <string.h>
#include <vector>
#include <queue>
#include <map>
#include <unordered_map>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<string, string> pss;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pii> vii;
typedef vector<ll> vl;
typedef vector<vl> vvl;
int n , k ;
bool visa[(int)3 * 100000];
vector <pair<int,int>> x[200002];
int best_path( int N, int K, int H[][2] ,int L[]) {
n = N;k = K;
for ( int i = 0 ; i < n-1 ; i++ ) {
x[H[i][0]].pb( { L[i] , H[i][1] } );
swap(H[i][0],H[i][1]);
x[H[i][0]].pb( { L[i] , H[i][1] } );
}
int mn = (int)1e6;
for ( int i = 0; i < n; i++ ) {
memset(visa,0,sizeof(visa));
queue <pair<ll,int>> q ;
q.push({0,i});
int z = 1 , layer = 0 ;
while ( !q.empty() ) {
if ( layer > k ) break;
int a = q.front().S; ll cst = q.front().F;
q.pop();
visa[a] = true;
cst *= -1 ;
if (cst == k) mn = min(mn,layer);
for (auto i:x[a]) {
if ( visa[i.S] ) continue ;
q.push( { -(cst+i.F) , i.S } );
}
z--;
if ( !z ) {
layer++;
z = q.size();
}
}
}
return (mn==(int)1e6?-1:mn) ;
}
