#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cmath>
#define ll long long
using namespace std;
const int mod=1e9+7;
const int MN=1e6+5;
const int rt=1;
ll n,q,val[MN],head[MN],tot,f[MN][3],deep[MN],x,ans[MN],res;
struct edge{ll to,nxt;}e[MN<<1];
void write(ll n){if(n<0){putchar('-');write(-n);return;}if(n>9)write(n/10);putchar(n%10+'0');}
ll read(){ll x=0,f=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}while(ch>='0'&&ch<='9'){x=(x<<1)+(x<<3)+(ch^48);ch=getchar();}return x*f;}
void add(ll u, ll v){e[++tot].nxt=head[u];head[u]=tot;e[tot].to=v;}
void build(ll u, ll fa){
	deep[u]=deep[fa]+1;
	for(int i=head[u]; i; i=e[i].nxt){
		ll v=e[i].to;
		if(v==fa) continue;
		build(v,u);
		f[u][1]^=f[v][0];f[u][2]^=f[v][1];
	}
}
void dfs(ll u){
	for(int i=head[u]; i; i=e[i].nxt){
		ll v=e[i].to;
		if(deep[v]<=deep[u]) continue;
		f[v][2]^=f[v][0];
		f[v][1]^=f[u][0];f[v][2]^=f[u][1];
		dfs(v);
	}
}
void change(ll u, ll lst, ll llst, ll step, ll v1, ll v2){
    if(step==3) return;
    for(int i=head[u]; i; i=e[i].nxt){
        ll v=e[i].to;
        if(v==lst||v==llst) continue;
        f[v][step]^=v1;f[v][step]^=v2;
        change(v,u,lst,step+1,v1,v2);
    }
}
int main(){
	n=read();q=read();
	for(int i=1; i<=n; i++) val[i]=f[i][0]=read();
	for(int i=1; i<n; i++){
		ll u=read(),v=read();
		add(u,v);add(v,u);
	}
	build(rt,0);dfs(rt);
	for(int i=1; i<=q; i++){
		x=read();ll num=f[x][0];f[x][0]=read();
        change(x,0,0,1,num,f[x][0]);
		ans[i]=f[x][0]^f[x][1]^f[x][2];
	}
	for(int i=1; i<=q; i++) res=(res+i*i%mod*ans[i]%mod)%mod;
	write(res);putchar('\n');
	return 0;
}