#include "closing.h"
#include<bits/stdc++.h>
#define Gc() getchar() 
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define eb emplace_back
using namespace std;using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;using pii=pair<int,int>;using LL=__int128;
const int N=2e5+5,M=5e5+5,K=(1<<25)+5,mod=998244353,Mod=mod-1;const db eps=1e-9;const int INF=1e9+7;mt19937 rnd(time(0));
int n;ll k;vector<pii> S[N];
ll d1[N],d2[N];
void Make(int x,int La,ll *d){
	for(auto i:S[x]) if(i.fi^La) d[i.fi]=d[x]+i.se,Make(i.fi,x,d);
}
int max_score(int nn,int X,int Y,ll kk,vector<int> U,vector<int> V,vector<int> W){
    int i,j;n=nn;k=kk;for(i=0;i<n;i++) S[i].clear();
	for(int i=0;i<n-1;i++) S[U[i]].emplace_back(V[i],W[i]),S[V[i]].emplace_back(U[i],W[i]);
	d1[X]=d2[Y]=0;Make(X,-1,d1);Make(Y,-1,d2);
	k*=2;
	for(int i=0;i<n;i++) d1[i]*=2,d2[i]*=2;
	priority_queue<pair<ll,int> > q;
	int ans=0, tot=0;
	for(i=0;i<n;i++) q.emplace(-d1[i],0),q.emplace(-d2[i],0);
	ll m=k;
	while(!q.empty()){
		auto p=q.top();q.pop();
		p.fi*=-1;
		if(m>=p.fi) m-=p.fi,tot++;
		else break;
	}
	ans=max(ans,tot);
	while(!q.empty()) q.pop();
	tot=0;m=k;
	for(i=0;i<n;i++) {
		if(d1[i]>d2[i]) swap(d1[i],d2[i]);
	}
	ll Le=d1[X]+d2[X];
	for(i=0;i<n;i++){
		if(d1[i]+d2[i]==Le){
			tot++;m-=min(d1[i],d2[i]);
			q.emplace(-abs(d1[i]-d2[i]),1);
		}else {
			d2[i]-=d1[i];
			if(d1[i]<=d2[i]) q.emplace(-d1[i],0),q.emplace(-d2[i],1);
			else q.emplace(-(d1[i]+d2[i])/2,-i);
		}
	} 
	ll mm=0;
	while(!q.empty()){
		auto p=q.top();q.pop();p.fi*=-1;p.se*=-1;
		// cerr<<tot<<' '<<m<<' '<<p.fi<<' '<<p.se<<'\n';
		if(m<p.fi) break;
		if(p.se==-1) {m-=p.fi;mm=max(mm,p.fi);tot++;continue;}
		if(m>=d1[p.se]+d2[p.se]) {m-=d1[p.se]+d2[p.se];tot+=2;continue;}
		if(m+mm>=d1[p.se]+d2[p.se]) {
			tot++;
			break;
		}
		q.emplace(-d1[p.se],1);
	}
	cerr<<m<<'\n';
	if(m>=0) ans=max(ans,tot);
	return ans;
}