```go
package main

import (
	"bufio"
	"io"
	"os"
	"strconv"
)

func main() {
	buf, _ := io.ReadAll(os.Stdin)
	pos := 0
	nextInt := func() int {
		for pos < len(buf) && buf[pos] <= ' ' {
			pos++
		}
		if pos >= len(buf) {
			return 0
		}
		res := 0
		for pos < len(buf) && buf[pos] > ' ' {
			res = res*10 + int(buf[pos]-'0')
			pos++
		}
		return res
	}

	n := nextInt()
	m := nextInt()
	if n == 0 {
		return
	}

	color := make([]int, n+1)
	for i := 1; i <= n; i++ {
		color[i] = nextInt()
	}

	adj := make([][]int, n+1)
	for i := 0; i < n-1; i++ {
		u, v := nextInt(), nextInt()
		adj[u] = append(adj[u], v)
		adj[v] = append(adj[v], u)
	}

	type Query struct {
		k, id int
	}
	queries := make([][]Query, n+1)
	for i := 0; i < m; i++ {
		v, k := nextInt(), nextInt()
		queries[v] = append(queries[v], Query{k, i})
	}

	ans := make([]int, m)
	size := make([]int, n+1)
	heavy := make([]int, n+1)
	for i := range heavy {
		heavy[i] = -1
	}

	var dfs1 func(int, int)
	dfs1 = func(u, p int) {
		size[u] = 1
		max_sub := 0
		for _, v := range adj[u] {
			if v != p {
				dfs1(v, u)
				size[u] += size[v]
				if size[v] > max_sub {
					max_sub = size[v]
					heavy[u] = v
				}
			}
		}
	}
	dfs1(1, 0)

	freq := make([]int, 100005)
	at_least := make([]int, 100005)

	var add_subtree func(int, int, int)
	add_subtree = func(u, p, val int) {
		if val == 1 {
			freq[color[u]]++
			at_least[freq[color[u]]]++
		} else {
			at_least[freq[color[u]]]--
			freq[color[u]]--
		}
		for _, v := range adj[u] {
			if v != p {
				add_subtree(v, u, val)
			}
		}
	}

	var dfs2 func(int, int, bool)
	dfs2 = func(u, p int, keep bool) {
		for _, v := range adj[u] {
			if v != p && v != heavy[u] {
				dfs2(v, u, false)
			}
		}
		if heavy[u] != -1 {
			dfs2(heavy[u], u, true)
		}
		for _, v := range adj[u] {
			if v != p && v != heavy[u] {
				add_subtree(v, u, 1)
			}
		}
		freq[color[u]]++
		at_least[freq[color[u]]]++

		for _, q := range queries[u] {
			if q.k <= 100000 {
				ans[q.id] = at_least[q.k]
			}
		}

		if !keep {
			add_subtree(u, p, -1)
		}
	}
	dfs2(1, 0, false)

	out := bufio.NewWriter(os.Stdout)
	for _, a := range ans {
		out.WriteString(strconv.Itoa(a) + "\n")
	}
	out.Flush()
}
```