#include "race.h"
#include<bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
#define all(a) a.begin(), a.end()
#define ff(i,a,b) for(int i=a;i<=b;i++)
#define fb(i,b,a) for(int i=b;i>=a;i--)
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
const int maxn = 200005;
const int inf = 1e9 + 5;
int n, k;
vector<pii> g[maxn];
int rez = inf;
int cnt[maxn];
bool bio[maxn];
void dfs_size(int v, int p){
cnt[v] = 1;
for(auto c : g[v]){
int u = c.fi;
// int w = c.se;
if(u == p || bio[u])continue;
dfs_size(u, v);
cnt[v] += cnt[u];
}
}
int centroid(int v, int p, int vel){
for(auto c : g[v]){
int u = c.fi;
// int w = c.se;
if(u == p || bio[u])continue;
if(cnt[u] > vel / 2)return centroid(u, v, vel);
}
return v;
}
int kol[5 * maxn];
vector<pii> cuvaj;
void dfs_resi(int v, int p, int duz, int pw){
if(pw > k)return;
// cout << "v: " << v << endl;
// cout << "d[v]: " << duz << endl;
// cout << "h[v]: " << pw << endl;
cuvaj.pb({pw, duz});
// cout << "rez: " << kol[k - d[v]] + h[v] << endl;
rez = min(rez, kol[k - pw] + duz);
// cout << endl;
for(auto c : g[v]){
int u = c.fi;
int w = c.se;
if(u == p || bio[u])continue;
dfs_resi(u, v, duz + 1, pw + w);
}
}
void decompose(int v, int p){
dfs_size(v, p);
int cen = centroid(v, p, cnt[v]);
// cout << endl;
// cout << "cen: " << cen << endl;
bio[cen] = 1;
vector<int> pom;
for(auto c : g[cen]){
int u = c.fi;
int w = c.se;
if(u == p || bio[u])continue;
cuvaj.clear();
dfs_resi(u, cen, 1, w);
for(auto c : cuvaj){
// cout << c.fi << " " << c.se << endl;
kol[c.fi] = min(kol[c.fi], c.se);
pom.pb(c.fi);
}
// cout << endl;
}
for(auto c : pom)kol[c] = inf;
for(auto c : g[cen]){
int u = c.fi;
// int w = c.se;
if(u == p || bio[u])continue;
decompose(u, cen);
}
}
int best_path(int N, int K, int H[][2], int L[]){
n = N;
k = K;
ff(i,0,n - 2){
g[H[i][0] + 1].pb({H[i][1] + 1, L[i]});
g[H[i][1] + 1].pb({H[i][0] + 1, L[i]});
}
rez = inf;
ff(i,1,5 * maxn - 1)kol[i] = inf;
decompose(1, -1);
return (rez > n ? -1 : rez);
}
//int main()
//{
// ios::sync_with_stdio(false);
// cout.tie(nullptr);
// cin.tie(nullptr);
// cin >> n >> k;
// ff(i,1,n - 1){
// int u, v, w;
// cin >> u >> v >> w;
// g[u].pb({v, w});
// g[v].pb({u, w});
// }
// ff(i,1,5 * maxn - 1)kol[i] = inf;
// decompose(1, -1);
// cout << (rez == inf ? -1 : rez) << endl;
// return 0;
//}
/**
4 3
1 2 1
2 3 2
2 4 4
3 3
1 2 1
2 3 1
11 12
1 2 3
1 3 4
3 4 5
4 5 4
5 6 6
1 7 3
7 8 2
7 9 5
9 10 6
9 11 7
6 7
1 2 1
1 3 1
2 5 3
2 4 8
5 6 2
**/
