#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e6+10;
int tree[MAXN];
int n,q;
int lowbit(int i){return i&(-i);}
void add(int i,int v){
    for(;i<=n;i+=lowbit(i))tree[i]^=v;
}
int query(int i){
    int re=0;
    for(;i;i-=lowbit(i))re^=tree[i];return re;
}
int Query(int l,int r){
    if(l>n||r<=0)return 0;
    return query(r)^query(l-1);
}
vector<int>e[MAXN];
int mx1[MAXN],mn1[MAXN],mx2[MAXN],mn2[MAXN];
int bfn[MAXN];
int fa[MAXN];
void dfs(int u,int f){fa[u]=f;
    for(int v:e[u])if(v!=f)dfs(v,u);
}int a[MAXN];
void bfs(){
    dfs(1,0);
    queue<int>q;q.push(1);int cnt=0;
    while(!q.empty()){
        int u=q.front();q.pop();
        bfn[u]=++cnt;
        for(int v:e[u])if(v!=fa[u])q.push(v);
    }
    for(int i=1;i<=n;++i)mn1[i]=mn2[i]=1e9,mx1[i]=mx2[i]=-1e9;
    for(int i=1;i<=n;++i){
        if(fa[i])mx1[fa[i]]=max(mx1[fa[i]],bfn[i]),mn1[fa[i]]=min(mn1[fa[i]],bfn[i]);
        if(fa[fa[i]]){
            int x=fa[fa[i]];mx2[x]=max(mx2[x],bfn[i]);mn2[x]=min(mn2[x],bfn[i]);
        }   
    }
    for(int i=1;i<=n;++i)add(bfn[i],a[i]);
}

int solve(int i,int v){
    add(bfn[i],a[i]);a[i]=v;add(bfn[i],a[i]);
    int re=0;
    if(fa[i]){re^=Query(mn1[fa[i]],mx1[fa[i]])^a[fa[i]];}
    else re^=a[i];
    if(fa[fa[i]])re^=a[fa[fa[i]]];
    re=re^Query(mn1[i],mx1[i])^Query(mn2[i],mx2[i]);
    return re;
}
const int mod = 1e9+7;
typedef long long ll;
int main(){
    scanf("%d%d",&n,&q);
    for(int i=1;i<=n;++i)scanf("%d",&a[i]);
    for(int i=1;i<n;++i){int u,v;scanf("%d%d",&u,&v);e[u].push_back(v),e[v].push_back(u);}
    bfs();
    ll ans=0;
    for(ll i=1;i<=q;++i){
        int x,y;scanf("%d%d",&x,&y);
        ans=(ans+solve(x,y)*i%mod*i%mod)%mod;
    }
    printf("%lld\n",ans);
    return 0;
}