#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
int read(){
    int red=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){ if(ch=='-') f=-f;ch=getchar();}
    while(ch>='0'&&ch<='9') red=red*10+ch-48,ch=getchar();
    return red*f;
}
LL LLread(){
    LL red=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){ if(ch=='-') f=-f;ch=getchar();}
    while(ch>='0'&&ch<='9') red=red*10+ch-48,ch=getchar();
    return red*f;
}
const int N=5e5+5,E=N<<1,inf=1<<30;
int n,q,a[N],f[N][21],dep[N],p1[N],p2[N];
LL S[N];
int son[E],nxt[E],lnk[N],tot,w[E];
void add_e(int x,int y,int z){
    son[++tot]=y,nxt[tot]=lnk[x],lnk[x]=tot,w[tot]=z;
}
#define v son[j]
void dfs(int x,int fa=0){
    f[x][0]=fa;
    for(int i=1;i<=20;i++) f[x][i]=f[f[x][i-1]][i-1];
    for(int j=lnk[x];j;j=nxt[j]) if(v^fa){
        S[v]=S[x]+w[j];dep[v]=dep[x]+1;
        dfs(v,x);
    }
}
int LCA(int x,int y){
    if(dep[x]>dep[y]) swap(x,y);
    for(int i=20;~i;i--) if(dep[f[y][i]]>=dep[x]) y=f[y][i];
    for(int i=20;~i;i--) if(f[x][i]^f[y][i]) x=f[x][i],y=f[y][i];
    return x==y?x:f[x][0];
}
LL dis(int x,int y){return S[x]+S[y]-2*S[LCA(x,y)];}
int id[N],Mex;
bool H[N];
bool cmp(int x,int y){return a[x]<a[y];}
bool check(int i,int x,LL k){
    return dis(p1[i],x)<=k&&dis(p2[i],x)<=k;
}
int main(){
    n=read(),q=read();
    for(int i=1;i<=n;i++) a[i]=read(),H[a[i]]=1,id[i]=i;a[n+1]=inf,id[n+1]=n+1;
    while(H[Mex]) Mex++;
    for(int i=1;i<n;i++){
        int x=read(),y=read(),z=read();
        add_e(x,y,z),add_e(y,x,z);
    }
    dfs(1);
    sort(id+1,id+1+n,cmp);p1[1]=id[1],p2[1]=id[1];
    for(int i=2;i<=n;i++){
        int x=id[i];
        p1[i]=p1[i-1],p2[i]=p2[i-1];
        LL now=dis(p1[i],p2[i]),Nxt;
        Nxt=dis(x,p2[i-1]);
        if(Nxt>now){
            now=Nxt;
            p1[i]=x;p2[i]=p2[i-1];
        }
        Nxt=dis(x,p1[i-1]);
        if(Nxt>now){
            now=Nxt;
            p1[i]=p1[i-1];p2[i]=x;
        }
    }
    while(q--){
        int x=read();LL k=LLread();
        int l=1,r=n,mid;
        while(l<=r){
            mid=l+r>>1;
            if(check(mid,x,k)) l=mid+1;
            else r=mid-1;
        }
        printf("%d\n",min(Mex,a[id[l]]));
    }
    return 0;
}