// Problem: A. 树与异或
// Contest: undefined - NOIP2024训练赛 10
// URL: http://www.noi.ac/contest/1162/problem/2376
// Memory Limit: 1024 MB
// Time Limit: 1000 ms
// 
// Powered by CP Editor (https://cpeditor.org)

#include<bits/stdc++.h>
#define int long long
#define fi first
#define se second
#define PII pair<int, int>

using namespace std;

const int N = 2e5 + 10, M = 1e6 + 10, mod = 1e9 + 7, INF = 0x3f3f3f3f;

int n, m, q, ans;
int s[N], dp[N][4], f[N];

vector<int> e[N];

void dfs(int now, int fa)
{
	dp[now][0] = s[now], f[now] = fa;
	for(auto i : e[now])
	{
		if(i == fa) continue;
		dfs(i, now);
		dp[now][1] ^= dp[i][0];
		dp[now][2] ^= dp[i][1];
	}
}

signed main()
{
	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	cin >> n >> q;
	for(int i = 1; i <= n; i ++) cin >> s[i];
	for(int i = 1; i < n; i ++)
	{
		int u, v; cin >> u >> v;
		e[u].push_back(v), e[v].push_back(u);
	}
	dfs(1, 1); 
	for(int i = 1; i <= q; i ++)
	{
		int x, v, res = 0; cin >> x >> v;
		if(x != 1) dp[f[x]][1] ^= v ^ dp[x][0], res ^= dp[f[x]][0] ^ dp[f[x]][1];
		if(f[x] != 1) dp[f[f[x]]][2] ^= v ^ dp[x][0], res ^= dp[f[f[x]]][0];
		dp[x][0] = v, res ^= dp[x][1] ^ dp[x][2];
		ans = (ans + (res * i % mod) * i % mod) % mod;
	}
	cout << ans << '\n';
	return 0;
}