//minamoto

 #include<iostream>

 #include<cstring>

 #include<cstdio>

 #define ll long long

 #define max(a,b) ((a)>(b)?(a):(b))

 #define getc() (p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<21,stdin),p1==p2)?EOF:*p1++)

 char buf[<<],*p1=buf,*p2=buf;

 template<class T>inline bool cmax(T&a,const T&b){return a<b?a=b,:;}

 using namespace std;

 inline ll read(){

     #define num ch-'0'

     char ch;bool flag=;ll res;

     while((ch=getc())>''||ch<'')

     (ch=='-')&&(flag=true);

     for(res=num;(ch=getc())<=''&&ch>='';res=res*+num);

     (flag)&&(res=-res);

     #undef num

     return res;

 }

 char sr[<<],z[];int C=-,Z;

 inline void Ot(){fwrite(sr,,C+,stdout),C=-;}

 inline void print(ll x){

     if(C><<)Ot();if(x<)sr[++C]=,x=-x;

     while(z[++Z]=x%+,x/=);

     while(sr[++C]=z[Z],--Z);sr[++C]='\n';

 }

 const int N=;

 int n,q,tot,head[N],Next[N<<],ver[N<<],dep[N];

 ll fa[N][],b[N][][],sum,ans[],val[N];

 inline void add(int u,int v){

     ver[++tot]=v,Next[tot]=head[u],head[u]=tot;

 }

 inline void get(ll *b,ll x){

     for(int i=;i>=;--i)

     if(x>>i&){

         if(!b[i]) return (void)(b[i]=x);

         x^=b[i];

     }

 }

 inline void merge(ll *b,ll *x){

     for(int i=;i>=;--i)

     if(x[i]) get(b,x[i]);

 }

 inline void init(int i){

     for(int j=;j<;++j){

         fa[i][j]=fa[fa[i][j-]][j-];

         memcpy(b[i][j],b[i][j-],sizeof(b[i][j-]));

         merge(b[i][j],b[fa[i][j-]][j-]);

     }

 }

 void dfs(int u,int f){

     fa[u][]=f,dep[u]=dep[f]+,init(u);

     for(int i=head[u];i;i=Next[i])

     if(ver[i]!=f) dfs(ver[i],u);

 }

 void LCA(int u,int v){

     if(dep[u]<dep[v]) swap(u,v);

     for(int i=;i>=;--i)

     if(dep[fa[u][i]]>=dep[v])

     merge(ans,b[u][i]),u=fa[u][i];

     if(u==v) return (void)(merge(ans,b[u][]));

     for(int i=;i>=;--i)

     if(fa[u][i]!=fa[v][i]){

         merge(ans,b[u][i]),merge(ans,b[v][i]);

         u=fa[u][i],v=fa[v][i];

     }

     merge(ans,b[u][]),merge(ans,b[v][]),merge(ans,b[fa[u][]][]);

 }

 int main(){

 //    freopen("testdata.in","r",stdin);

     n=read(),q=read();

     for(int i=;i<=n;++i)

     get(b[i][],val[i]=read());

     for(int i=,u,v;i<n;++i)

     u=read(),v=read(),add(u,v),add(v,u);

     dfs(,);

     while(q--){

         memset(ans,,sizeof(ans));

         int u=read(),v=read();

         LCA(u,v);

         sum=;

         for(int i=;i>=;--i)

         cmax(sum,sum^ans[i]);

         print(sum);

     }

     Ot();

     return ;

 }