#include<bits/stdc++.h>

using namespace std;

#define il inline

#define ll long long

#define int long long

#define gc getchar()

#define mp make_pair

#define t(i) edge[i].to

#define ri register int

#define rb register bool

#define rc register char

#define rp(i,x,y) for(ri i=x;i<=y;++i)

#define my(i,x,y) for(ll i=x;i>=y;--i)

#define e(i,x) for(ri i=head[x];i;i=edge[i].nxt)

const int N=;

int n,q,poww[]={},val[N],ed_cnt,head[N],hs[N],sz[N],dfn[N],dfn_cnt,top[N],lg[N],fa[N],dep[N];

struct ed{int to,nxt;}edge[N<<];

struct xxj

{

    ll a[];int num_cnt;

    il void clr(){memset(a,,sizeof(a));num_cnt=;}

    il void insert(ll x){if(num_cnt==)return;my(i,,)if(x&poww[i]){x^=a[i];if(!a[i]){a[i]=x,++num_cnt;return;}}}

    il ll mx(){ll ret=;my(i,,)ret=max(ret,ret^a[i]);return ret;}

}gdgs[][N],as;

il int read()

{

    rc ch=gc;ri x=;rb y=;

    while(ch!='-' && (ch<'' || ch>''))ch=gc;

    if(ch=='-')ch=gc,y=;

    while(ch>='' && ch<='')x=(x<<)+(x<<)+(ch^''),ch=gc;

    return y?x:-x;

}

il void ad(ri x,ri y){edge[++ed_cnt]=(ed){x,head[y]};head[y]=ed_cnt;edge[++ed_cnt]=(ed){y,head[x]};head[x]=ed_cnt;}

void dfs1(ri x,ri fat)

{

    sz[x]=;fa[x]=fat;dep[x]=dep[fat]+;

    e(i,x)if(fat^t(i)){dfs1(t(i),x);sz[x]+=sz[t(i)];if(sz[t(i)]>sz[hs[x]])hs[x]=t(i);}

}

void dfs2(ri x,ri tp)

{

    top[x]=tp;dfn[x]=++dfn_cnt;gdgs[][dfn_cnt].insert(val[x]);

    if(hs[x])dfs2(hs[x],tp);e(i,x)if(!dfn[t(i)])dfs2(t(i),t(i));

}

il xxj merg(xxj gd,xxj gs){rp(i,,){if(gd.num_cnt==)return gd;if(gs.a[i])gd.insert(gs.a[i]);}return gd;}

il xxj gt(ri l,ri r){ri ln=lg[r-l+];return merg(gdgs[ln][l],gdgs[ln][r-poww[ln]+]);}

main()

{

//    freopen("3292.in","r",stdin);freopen("3292.out","w",stdout);

    rp(i,,)poww[i]=poww[i-]<<;

    n=read();q=read();rp(i,,n)val[i]=read();rp(i,,n-){ri x=read(),y=read();ad(x,y);}dfs1(,);dfs2(,);

    rp(i,,n)lg[i]=lg[i>>]+;rp(j,,lg[n])rp(i,,n+-poww[j])gdgs[j][i]=merg(gdgs[j-][i],gdgs[j-][i+poww[j-]]);

    while(q--)

    {

        ri x=read(),y=read();as.clr();

        while(top[x]!=top[y]){if(dep[top[x]]<dep[top[y]])swap(x,y);as=merg(gt(dfn[top[x]],dfn[x]),as);x=fa[top[x]];}

        if(dep[x]<dep[y])swap(x,y);as=merg(gt(dfn[y],dfn[x]),as);printf("%lld\n",as.mx());

    }

    return ;

}