1 //幸运数字
  2 #include<iostream>
  3 #include<cstdio>
  4 #define MAXN 20010
  5 #define LL long long
  6 const int L=1<<20|1;
  7 char buffer[L],*S,*T;
  8 #define getchar() ((S==T&&(T=(S=buffer)+fread(buffer,1,L,stdin),S==T))?EOF:*S++)
  9 using namespace std;
 10 struct xxj
 11 {
 12     LL b[65];
 13     void qk()
 14     {
 15         for(int i=0;i<=64;i++)b[i]=0;
 16     }
 17     bool ins(LL x)
 18     {
 19         for(int i=60;i>=0;i--)
 20         if(x&(1ll<<i))
 21         {
 22             if(!b[i]){b[i]=x;break;}
 23             else x=x^b[i];
 24         }
 25         if(x)return 1;
 26         else return 0;
 27     }
 28     LL findmax()
 29     {
 30         LL ans=0;
 31         for(int i=60;i>=0;i--)
 32             ans=max(ans,ans^b[i]);
 33         return ans;
 34     }
 35 }A[MAXN][16],ta;
 36 xxj hb(xxj a,xxj b)
 37 {
 38     xxj ans;ans.qk();
 39     for(int i=0;i<=60;i++)
 40     {
 41         if(a.b[i])ans.ins(a.b[i]);
 42         if(b.b[i])ans.ins(b.b[i]);
 43     }
 44     return ans;
 45 }
 46 struct edge
 47 {
 48     int u,v,nxt;
 49     #define u(x) ed[x].u
 50     #define v(x) ed[x].v
 51     #define n(x) ed[x].nxt
 52 }ed[MAXN*2];
 53 int first[MAXN],num_e;
 54 #define f(x) first[x]
 55 LL n,q,g[MAXN];
 56 int fa[MAXN][16],dep[MAXN];
 57 void dfs(int x,int ff,int de)
 58 {
 59     fa[x][0]=ff;dep[x]=de;A[x][0].ins(g[x]);//A[x][0].ins(g[ff]);
 60     for(int i=f(x);i;i=n(i))
 61     if(v(i)!=ff)dfs(v(i),x,de+1);
 62 }
 63 int LCA(int x,int y)
 64 {
 65     if(dep[x]>dep[y])swap(x,y);
 66     for(int i=15;i>=0;i--)
 67         if(dep[fa[y][i]]>=dep[x])
 68             y=fa[y][i];
 69     if(x==y)return x;
 70     for(int i=15;i>=0;i--)
 71         if(fa[x][i]!=fa[y][i])
 72             x=fa[x][i],y=fa[y][i];
 73     return fa[x][0];
 74 }
 75 inline LL read()
 76 {
 77     LL s=0;char a=getchar();
 78     while(a<'0'||a>'9')a=getchar();
 79     while(a>='0'&&a<='9'){s=s*10+a-'0';a=getchar();}
 80     return s;
 81 }
 82 inline void adde(int u,int v);
 83 signed main()
 84 {
 85 //    freopen("10.in","r",stdin);
 86
 87     n=read(),q=read();
 88     for(int i=1;i<=n;i++)g[i]=read();
 89     int a,b;
 90     for(int i=1;i<n;i++)
 91     {
 92         a=read(),b=read();
 93         adde(a,b);adde(b,a);
 94     }
 95     dfs(1,0,1);
 96     for(int i=1;i<=15;i++)
 97         for(int j=1;j<=n;j++)
 98         {
 99             fa[j][i]=fa[fa[j][i-1]][i-1];
100             A[j][i]=hb(A[j][i-1],A[fa[j][i-1]][i-1]);
101         }
102     for(int i=1;i<=q;i++)
103     {
104         int xi=read(),yi=read();
105         int lca=LCA(xi,yi);
106         ta.qk();
107         for(int j=15;j>=0;j--)
108         if(dep[fa[xi][j]]>=dep[lca])
109             ta=hb(ta,A[xi][j]),xi=fa[xi][j];
110         for(int j=15;j>=0;j--)
111         if(dep[fa[yi][j]]>=dep[lca])
112             ta=hb(ta,A[yi][j]),yi=fa[yi][j];
113         ta.ins(g[lca]);
114         printf("%lld\n",ta.findmax());
115     }
116 }
117 inline void adde(int u,int v)
118 {
119     ++num_e;
120     u(num_e)=u;
121     v(num_e)=v;
122     n(num_e)=f(u);
123     f(u)=num_e;
124 }