#include <bits/stdc++.h>

typedef long long ll;
const int N = 400054, M = N * 2;

int n, E = 0;
int to[M], first[N], next[M];
int p[N], prf[N];
ll a[N], sa[N], f[N];
ll ans = 0;

inline ll min(const ll x, const ll y) {return x < y ? x : y;}
inline ll max(const ll x, const ll y) {return x < y ? y : x;}

inline void addedge(int u, int v) {
	to[++E] = v, next[E] = first[u], first[u] = E;
	to[++E] = u, next[E] = first[v], first[v] = E;
}

// V : a[] + virtual sum (v + as)
// sa : sum of V (s + st, sum of v + sum of as)
namespace LCT {
	#define pa p[nd]
	struct node {ll v, sa; int p, c[2];} nd[N];
	inline int dir(int x) {return !nd[x].p ? -1 : x == nd[x].pa.c[0] ? 0 : x == nd[x].pa.c[1] ? 1 : -1;}
	inline void update(int x) {const int l = nd[x].c[0], r = nd[x].c[1]; nd[x].sa = nd[x].v + nd[l].sa + nd[r].sa;}
	void rotate(int x) {
		int y = nd[x].p, d = !dir(x);
		nd[nd[y].c[!d] = nd[x].c[d]].p = y;
		nd[x].p = nd[y].p;
		if (~dir(y)) nd[y].pa.c[dir(y)] = x;
		nd[nd[x].c[d] = y].p = x;
		update(y);
	}
	void splay(int x) {for (; ~dir(x); rotate(x)) if (~dir(nd[x].p)) rotate(dir(x) ^ dir(nd[x].p) ? x : nd[x].p); update(x);}
	void access(int x, int val) {
		a[x] += val;
		for (int r, y = 0; x; y = x, x = nd[x].p) {
			splay(x), r = nd[x].c[1];
			nd[x].v += val, nd[x].sa += val;
			ll sum = nd[x].v + nd[r].sa;
			if (r && nd[r].sa * 2 <= sum) nd[x].v += nd[r].sa, nd[x].c[1] = 0;
			if (y && nd[y].sa * 2 > sum) nd[x].v -= nd[y].sa, nd[x].c[1] = y;
			ans -= f[x], ans += f[x] = min(sum - 1, 2 * (sum - max(a[x], nd[x].c[1][nd].sa)));
			update(x);
		}
	}
}

void dfs(int x) {
	int i, y, &z = prf[x]; sa[x] = a[x];
	for (i = first[x]; i; i = next[i])
		if ((y = to[i]) != p[x])
			p[y] = x, dfs(y), sa[x] += sa[y], sa[y] > sa[z] ? z = y : 0;
	ans += f[x] = min(sa[x] - 1, 2 * (sa[x] - max(a[x], sa[z])));
}

int main() {
	int i, u, v, q;
	scanf("%d%d", &n, &q);
	for (i = 1; i <= n; ++i) scanf("%lld", a + i);
	for (i = 1; i < n; ++i) scanf("%d%d", &u, &v), addedge(u, v);
	dfs(1), printf("%lld\n", ans);
	for (i = 1; i <= n; ++i) {
		LCT::nd[i].p = p[i], LCT::nd[i].v += LCT::nd[i].sa = sa[i];
		if (sa[prf[i]] * 2 > sa[i]) LCT::nd[i].c[1] = prf[i], LCT::nd[i].v -= sa[prf[i]];
	}
	for (; q; --q)
		scanf("%d%d", &u, &v), LCT::access(u, v), printf("%lld\n", ans);
	return 0;
}