#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e6+10;
vector<int>e[MAXN];
int cnt[MAXN];
int f[MAXN];
int n,q;
int v[MAXN];
int calc(int x){
    int re=v[x];
    for(int u:e[x]){
        re^=v[u];
        for(int V:e[u]){
            if(V==x)continue;re^=v[V];
        }
    }
    return re;
}
typedef long long ll;
const int mod = 1e9+7;
int main(){
    scanf("%d%d",&n,&q);
    for(int i=1;i<=n;++i)scanf("%d",&v[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);}
    ll ans=0;
    for(int i=1;i<=q;++i){
        int x,y;scanf("%d%d",&x,&y);v[x]=y;
        ans=(ans+calc(x)*i*i%mod)%mod;
    }
    cout<<ans<<endl;
    return 0;
}