#include<cstdio>
#include<iostream>
#include<vector>
#include<cstring>
#include<cmath>
#include<cctype>
#include<algorithm>
using namespace std;
typedef long long ll;
const int N=20010;
const int BASE=60;
const int LOGN=15;
inline ll read(){ll X=0,w=0;char ch=0;while(!isdigit(ch)){w|=ch=='-';ch=getchar();}while(isdigit(ch))X=(X<<3)+(X<<1)+(ch^48),ch=getchar();return w?-X:X;
}
struct node{int to,nxt;
}e[N*2];
struct basis{ll c[BASE+2];
}b[N][LOGN+2];
int n,q,cnt,head[N],dep[N];
int anc[N][LOGN+2];
inline void add(int u,int v){e[++cnt].to=v;e[cnt].nxt=head[u];head[u]=cnt;
}
void ins(ll k,basis &a){for(int i=BASE;i>=0;i--)if(k>>i&1)if(a.c[i])k^=a.c[i];else{a.c[i]=k;break;}
}
basis merge(basis a,basis b){for(int i=BASE;i>=0;i--)if(b.c[i])ins(b.c[i],a);return a;
}
void dfs(int u){dep[u]=dep[anc[u][0]]+1;for(int i=1;i<=LOGN;i++){anc[u][i]=anc[anc[u][i-1]][i-1];b[u][i]=merge(b[u][i-1],b[anc[u][i-1]][i-1]);}for(int i=head[u];i;i=e[i].nxt){int v=e[i].to;if(v!=anc[u][0]){anc[v][0]=u;dfs(v);}}
}
ll getans(basis a){ll ans=0;for(int i=BASE;i>=0;i--)ans=max(ans,ans^a.c[i]);return ans;
}
ll query(int i,int j){static basis t1,t2;memset(t1.c,0,sizeof(t1.c));memset(t2.c,0,sizeof(t2.c));if(dep[i]<dep[j])swap(i,j);for(int k=LOGN;k>=0;k--){if(dep[anc[i][k]]>=dep[j]){t1=merge(t1,b[i][k]);i=anc[i][k];}}if(i==j)return getans(merge(t1,b[i][0]));for(int k=LOGN;k>=0;k--){if(anc[i][k]!=anc[j][k]){t1=merge(t1,b[i][k]);t2=merge(t2,b[j][k]);i=anc[i][k],j=anc[j][k];}}t1=merge(t1,b[i][0]);t2=merge(t2,b[j][0]);return getans(merge(merge(t1,t2),b[anc[i][0]][0]));
}
int main(){n=read(),q=read();for(int i=1;i<=n;i++)ins(read(),b[i][0]);for(int i=1;i<n;i++){int u=read(),v=read();add(u,v);add(v,u);}dfs(1);for(int i=1;i<=q;i++){int u=read(),v=read();printf("%lld\n",query(u,v));}return 0;
}