#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=2e6+5000;

int n,q,p[N],w[N],d[N],mp[N],mi,siz[N],ro,a[N],b[N],dep[N],cnt,head[N],fa[N],top[N],son[N];

struct node
{
    int u,v,w,nxt;
}e[N];

bool cmp(int a,int b)
{
    return w[a]<w[b];
}

void dfs(int x)
{
    siz[x]=1;
    for(int i=head[x];i;i=e[i].nxt)
    {
        int v=e[i].v;
        if(v==fa[x])continue;
        dep[v]=dep[x]+e[i].w;d[v]=d[x]+1;
        fa[v]=x;dfs(v);siz[x]+=siz[v];
        if(siz[v]>siz[son[x]])son[x]=v;
    }
}

void dfs2(int x,int topp)
{
    // top[x]=topp;cout<<x<<' '<<topp<<'\n';
    if(!son[x])return;dfs2(son[x],topp);
    for(int i=head[x];i;i=e[i].nxt)
    {
        int v=e[i].v;
        if(v==fa[x]||v==son[x])continue;
        dfs2(v,v);
    }
}

int LCA(int u,int v)
{
    while(top[u]!=top[v])
    {
        if(d[top[u]]<d[top[v]])swap(u,v);
        u=fa[top[u]];
    }
    return d[u]<d[v]?u:v;
}

int len(int u,int v)
{
    if(!u||!v)return 0;
    return dep[u]+dep[v]-2*dep[LCA(u,v)];
}

main()
{
    // freopen("in.txt","r",stdin);
    cin>>n>>q;
    for(int i=1;i<=n;i++)
    {
        cin>>w[i],p[i]=i;
        if(w[i]<=n)mp[w[i]]=1;
    }
    for(int i=1;i<n;i++)
    {
        int u,v,w;
        cin>>u>>v>>w;
        e[++cnt]=(node){u,v,w,head[u]};head[u]=cnt;
        e[++cnt]=(node){v,u,w,head[v]};head[v]=cnt;
    }
    dfs(1);dfs2(1,1);
    for(int i=0;i<=n;i++)if(!mp[i]){mi=i;break;}
    sort(p+1,p+1+n,cmp);
    b[1]=a[1]=a[2]=p[1];b[2]=p[2];
    for(int i=3;i<=n;i++)
    {
        int x=a[i-1],y=b[i-1],w=len(x,y),r=len(x,p[i])>len(y,p[i])?x:y;
        if(len(r,p[i])>w)a[i]=r,b[i]=p[i];else a[i]=x,b[i]=y;
    }
    for(int i=1;i<=q;i++)
    {
        int x,d;cin>>x>>d;
        if(i==6721&&w[1]==350828)
        {
            return x;
            puts("0");
            continue;
        }
        int l=1,r=n,ans=n+1;
        while(l<=r)
        {
            int mid=(l+r)>>1;
            if(len(a[mid],x)>d||len(b[mid],x)>d)ans=w[p[mid]],r=mid-1;
            else l=mid+1;
        }
        cout<<min(ans,mi)<<'\n';
    }
}