#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define MP make_pair
mt19937 rnd(time(0));
const int MAXN=5e5+5;
int n,m,q,a[MAXN],tsiz,mson;
int eu[MAXN],ev[MAXN],ew[MAXN],siz[MAXN],maxx[MAXN];
int col[MAXN],ans[MAXN];
ll dis[MAXN];bool vis[MAXN],isw[MAXN];
struct query{ll id,d;};
struct info{int op,fr;ll d;};
vector<query> vec[MAXN];
vector<int> edg[MAXN];
info f[MAXN<<1];
void get_size(int u,int fa){
	siz[u]=maxx[u]=1;
	for(int id:edg[u]){
		int v=eu[id]^ev[id]^u;
		if(v==fa||vis[v]) continue;
		get_size(v,u);
		maxx[u]=max(maxx[u],siz[v]);
		siz[u]+=siz[v];
	}
	maxx[u]=max(maxx[u],tsiz-siz[u]);
	if(maxx[u]<maxx[mson]) mson=u;
}
void get_col(int u,int fa){
	for(int id:edg[u]){
		int v=eu[id]^ev[id]^u;
		if(v==fa||vis[v]) continue;
		col[v]=col[u];dis[v]=dis[u]+ew[id];
		get_col(v,u);
	}
	return;
}
void get_info(int u,int fa){
	f[++m]=(info){0,u,dis[u]};
	for(auto q:vec[u]) f[++m]=(info){col[u],q.id,q.d-dis[u]};
	for(int id:edg[u]){
		int v=eu[id]^ev[id]^u;
		if(v==fa||vis[v]) continue;
		get_info(v,u);
	}
}
void dfz(int u){
	// cout<<"Dfz at "<<u<<'\n';
	vis[u]=true;col[u]=u;dis[u]=0;
	for(int id:edg[u]){
		int v=eu[id]^ev[id]^u;
		if(vis[v]) continue;
		col[v]=v;dis[v]=ew[id];
		get_col(v,u);
	}
	m=0;
	get_info(u,0);
	sort(f+1,f+m+1,[&](info x,info y){
		if(x.d!=y.d) return x.d>y.d;
		return x.op>y.op;
	});
	int mn1=1e9,fr1=0,mn2=1e9,fr2=0;
	for(int i=1;i<=m;i++){
		if(f[i].op==0){
			if(mn1>a[f[i].fr]){
				if(col[f[i].fr]!=col[fr1]) mn2=mn1,fr2=fr1;
				mn1=a[f[i].fr];fr1=col[f[i].fr];
			}else if(col[f[i].fr]!=col[fr1]&&mn2>a[f[i].fr]){
				mn2=a[f[i].fr];fr2=col[f[i].fr];
			}
		}else{
			if(fr1!=f[i].op) ans[f[i].fr]=min(ans[f[i].fr],mn1);
			else ans[f[i].fr]=min(ans[f[i].fr],mn2);
		}
	}
	for(int id:edg[u]){
		int v=eu[id]^ev[id]^u;
		if(vis[v]) continue;
		mson=0;tsiz=siz[v];
		get_size(v,0);get_size(mson,0);dfz(mson);
	}
	return;
}
int main(){
	ios::sync_with_stdio(false);
	// freopen("Otomachi_Una.in","r",stdin);
	// freopen("Otomachi_Una.out","w",stdout);
	cin>>n>>q;
	for(int i=1;i<=n;i++){
		cin>>a[i];
		if(a[i]<=n) isw[a[i]]=true;
	}
	int mn=0;
	while(isw[mn]) mn++;
	for(int i=1;i<n;i++){
		cin>>eu[i]>>ev[i]>>ew[i];
		edg[eu[i]].push_back(i);
		edg[ev[i]].push_back(i);
	}
	for(int i=1;i<=q;i++){
		ll x,k;cin>>x>>k;
		vec[x].push_back((query){i,k});
		ans[i]=mn;
	}
	maxx[0]=1e9;
	tsiz=n;
	get_size(1,0);get_size(mson,0);
	dfz(mson);
	for(int i=1;i<=q;i++) cout<<ans[i]<<'\n';
	cerr<<clock();
	return 0;
}