#include<bits/stdc++.h>
#define int long long
using namespace std;
int n, m, a[200005], l[200005], r[200005], t[200005], ccnt, head[200005], nxt[400005], to[400005], fa[200005], num[200005], vis[200005];
int ans, in[200005];
inline void add(int p, int q) {
	nxt[++ccnt] = head[p];
	to[ccnt] = q;
	head[p] = ccnt;
}
struct node {
	int l, r, maxa, maxb, tag;
	inline node  operator+ (const node& p)const {
		node op;
		op.l = l, op.r = p.r;
		if (maxa > p.maxa) {
			op.maxa = maxa;
			op.maxb = maxb;
		} else {
			op.maxa = p.maxa;
			op.maxb = p.maxb;
		}
		op.tag = 0;
		return op;
	}
} b[800005];
inline void push_down(int p) {
	if (b[p].tag != 0 && b[p].l != b[p].r) {
		b[2 * p].tag += b[p].tag;
		b[2 * p + 1].tag += b[p].tag;
		b[2 * p].maxa += b[p].tag;
		b[2 * p + 1].maxa += b[p].tag;
		b[p].tag = 0;
		return;
	}
}
inline void dfs(int p, int q) {
	fa[p] = q;
	num[p] = num[q] + a[p];
	int flg = 1;
	l[p] = 0x3f3f3f3f, r[p] = -1;
	for (int i = head[p]; i; i = nxt[i]) {
		if (to[i] != q) {
			flg = 0;
			dfs(to[i], p);
			l[p] = min(l[to[i]], l[p]), r[p] = max(r[p], r[to[i]]);
		}
	}
	if (flg) {
		t[++ccnt] = p;
		l[p] = ccnt, r[p] = ccnt;
		return;
	}
}
inline void build(int p, int l, int r) {
//	cout << p << " " << l << " " << r << '!';
	b[p].l = l, b[p].r = r;
	b[p].tag = 0;
	if (l == r) {
//		cout << t[l] << "[]" << num[t[l]] << "[]\n";
		b[p].maxb = l, b[p].maxa = num[t[l]];
		return;
	}
	build(2 * p, l, (l + r) >> 1);
	build(2 * p + 1, ((l + r) >> 1) + 1, r);
	b[p] = b[2 * p] + b[2 * p + 1];
}
inline void change(int p, int l, int r, int w) {
	if (b[p].l >= l && b[p].r <= r) {
		b[p].maxa += w;
		b[p].tag += w;
		return;
	}
	push_down(p);
	int mid = (b[p].l + b[p].r) >> 1;
	if (r <= mid) change(2 * p, l, r, w);
	else if (l > mid) change(2 * p + 1, l, r, w);
	else change(2 * p, l, mid, w), change(2 * p + 1, mid + 1, r, w);
	b[p] = b[2 * p] + b[2 * p + 1];
}
inline void solve(int p) {
	while (!vis[p] && p != 0) {
		vis[p] = 1;
//		cout << l[p] << " " << r[p] << " " << -a[p] << "!";
		change(1, l[p], r[p], -a[p]);
		p = fa[p];
	}
}
signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin >> n >> m;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	int p, q;
	for (int i = 1; i < n; i++) {
		cin >> p >> q;
		in[q]++;
		add(p, q);
	}
	int rt = 0;
	for (int i = 1; i <= n; i++) {
		if (in[i] == 0) {
			rt = i;
			break;
		}
	}
	ccnt = 0;
	dfs(rt, 0);
	build(1, 1, ccnt);
	for (int i = 1; i <= m; i++) {
		int op = t[b[1].maxb];
		ans += b[1].maxa;
		solve(op);
	}
	cout << ans;
}