#include <queue>
#include <cstdio>
#include <cstring>
#include <algorithm>
int v, c;
template <class T> T read(T& x) {
	x = 0; v = 1; c = getchar();
	for (; c < '0' || c > '9'; c = getchar()) if (c == '-') v = -1;
	for (; c >= '0' && c <= '9'; c = getchar()) x = (x << 3) + (x << 1) + (c ^ 48);
	return x *= v;
}
const int N = 2000010;
int n, K, x, y, ans, a[N], id[N], b[N], br[N], t[N];
int cnt, head[N], fa[N];
bool vis[N];
struct Edge {
	int y, nxt;
} e[N];
inline void add(int x, int y) {
	e[++cnt].y = y; e[cnt].nxt = head[x]; head[x] = cnt;
}
inline bool cmp(int x, int y) {return a[x] > a[y];}
void dfs(int x, int faz) {
	fa[x] = faz;
	for (int i = head[x]; i; i = e[i].nxt) {
		int y = e[i].y;
		if (y != faz) dfs(y, x);
	}
}
bool chek(int x) {
	if (!fa[x]) return 1;
	for (int i = 1; id[i] != x; ++i) {
		if (!vis[id[i]]) continue;
		if (fa[x] == id[i]) return 1;
	}
	return 0;
}
struct Node {
	int x, val;
	Node() {}
	Node(int _, int __) {this -> x = _; this -> val = __;}
	bool operator< (const Node& b) const {return val < b.val;}
};
std::priority_queue <Node> q;
void dijk(int s) {
	vis[s] = 1;
	q.push(Node(s, a[id[1]]));
	for (; !q.empty(); ) {
		Node f = q.top(); q.pop();
		int x = f.x;
		if (br[a[x] + 1] != t[a[x] + 1]) continue;
		vis[x] = 1;
		++t[a[x]]; ++ans;
		if (ans == K) break;
		for (int i = head[x]; i; i = e[i].nxt) {
			int y = e[i].y;
			if (y != fa[x]) q.push(Node(y, a[id[y]]));
		}
	}
}
int main() {
	freopen("green.in", "r", stdin);
	freopen("green.out", "w", stdout);
	read(n); read(K);
	for (int i = 1; i <= n; ++i) {
		b[i] = read(a[i]);
		id[i] = i;
	}
	for (int i = 1; i < n; ++i) {
		read(x); read(y);
		++x; ++y;
		add(x, y); add(y, x);
	}
	std::sort(id + 1, id + n + 1, cmp);
	if (n <= 2000) {
		dfs(id[1], 0);
		for (int i = 1; i <= K; ++i) {
			if (chek(id[i])) {
				vis[id[i]] = 1;
				++ans;
			}
		}
		printf("%d\n", ans);
		return 0;
	}
	for (int i = 1; i <= n; ++i) {
		b[i] = a[i];
	}
	std::sort(b + 1, b + n + 1);
	cnt = std::unique(b + 1, b + n + 1) - b - 1;
	for (int i = 1; i <= n; ++i) {
		a[i] = std::lower_bound(b + 1, b + cnt + 1, a[i]) - b;
		++br[a[i]];
	}
	dijk(id[1]);
	printf("%d\n", ans);
	return 0;
}