// Olimpíadas Nacionais de Informática 2020
// Treino #01: Problema F - Festa de Aniversário
// Transcrição da solução oficial (convertida de C++ para Java)

import java.util.*;

class Interval {
    int lo, hi;

    Interval(int l, int h) {
	lo = l;
	hi = h;
    }
}

class f {
    //#define lo first
    //#define hi second

    static final int MAXN = 10010;
    static final int MAXK = 110;

    static int n, v[];

    static Vector<Vector<Integer>>  e = new Vector<>();
    static Vector<Vector<Interval>> s = new Vector<>();
    static Vector<Vector<Integer>>  q = new Vector<>();
    static BitSet[][] flag;

    static void dfs(int x) {
	for (int y : e.get(x)) 
	    dfs(y);

	for (int i = 0; i < MAXK; ++i)
	    q.get(i).clear();
	for (int y : e.get(x)) {
	    for (Interval it : s.get(y))
		q.get(it.lo).add(it.hi);
	}
  
	for (int lo = MAXK - 1; lo >= 1; --lo) {
	    if (lo == v[x]) {
		flag[x][lo].or(flag[x][lo + 1]);
		flag[x][lo].set(lo);
	    } else {
		for (int hi : q.get(lo)) {
		    if (hi < v[x] || lo > v[x]) {
			flag[x][lo].or(flag[x][hi + 1]);
			flag[x][lo].set(hi);
		    }
		}
	    }
	    
	    for (int hi = MAXK - 1; hi >= lo; --hi)
		if (flag[x][lo].get(hi) && v[x] >= lo && v[x] <= hi) {
		    s.get(x).add(new Interval(lo, hi));
		}
	}
    }
    
    static void init() {
	Scanner in = new Scanner(System.in);
	n = in.nextInt();

	flag = new BitSet[n][MAXK];
	for (int i=0; i<n; i++)
	    for (int j=0; j<MAXK; j++)
		flag[i][j] = new BitSet(MAXK);
	for (int i=0; i<n; i++) e.add(new Vector<Integer>());
	for (int i=0; i<n; i++) s.add(new Vector<Interval>());
	for (int i=0; i<MAXK; i++) q.add(new Vector<Integer>());
	
	v = new int[n];	
	for (int i = 0; i < n; ++i)
	    v[i] = in.nextInt();
	for (int i = 0; i < n - 1; ++i) {
	    int a = in.nextInt();
	    int b = in.nextInt();
	    --a;
	    --b;
	    e.get(a).add(b);
	}
    }
    
    static void solve() {
	dfs(0);
	System.out.println(s.get(0).size());
    }

    public static void main(String[] args) {
	init();
	solve();
    }
    
}