#include "race.h"
#include <vector>
#include <climits>
#include <algorithm>
#include <iostream>
using namespace std;
#define pii pair<int,int>
vector<int> dp[105];
vector<int> suf[105];
vector<vector<pii>> g;
int ans = INT_MAX;
void dfs(int v,int p){
dp[0][v] = 0;
for(auto k : g[v]){
if(k.first != p){
for(int i=0;i<=100-k.second;i++){
dp[i+k.second][k.first] = min(dp[i+k.second][k.first], dp[i][v]+1);
}
dfs(k.first, v);
for(int i=0;i<=100-k.second;i++){
dp[i+k.second][v] = min(dp[i+k.second][v], suf[i][k.first]+1);
suf[i+k.second][v] = min(suf[i+k.second][v], suf[i][k.first]+1);
}
}
}
suf[0][v] = 0;
}
int best_path(int N, int K, int H[][2], int L[]){
int n = N;
int k = K;
int a,b,c;
g.resize(n+1);
for(int i=0;i<n-1;i++){
a = H[i][0];
b = H[i][1];
c = L[i];
g[a].push_back({b,c});
g[b].push_back({a,c});
}
for(int i=0;i<=100;i++){
dp[i].resize(n+1, INT_MAX);
suf[i].resize(n+1, INT_MAX);
}
dfs(1,-1);
for(int i=0;i<n;i++){
ans = min(dp[k][i], ans);
}
if(ans==INT_MAX)
return -1;
return ans;
}
