import java.util.*;
import java.io.*;

public class ClockTree {
	static int N;
	static int[] ct;
	static ArrayList<Integer>[] adj;
	static int[] numcons;
	static boolean fail = false;

	public static void dfs(int na, int[]ctcp, int[]nccy){
		if(fail)
			return;
		for (int nb: adj[na]){
			if (fail)
				return;
			if(ctcp[nb] >= 12 && nccy[na] ==1)
			{
				fail = true;
				return;
			}
			if (ctcp[nb] <12){
				ctcp[nb]++;
				dfs(nb,ctcp,nccy);
			}
		}
	}

	public static void main(String[] args) throws Exception{
		BufferedReader br= new BufferedReader (new InputStreamReader (System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());
		N = Integer.parseInt(st.nextToken());
		ct = new int[N+1];
		st = new StringTokenizer (br.readLine());

		for(int i = 1; i <= N; ++i){
			ct[i] = Integer.parseInt(st.nextToken());
		}
		adj = new ArrayList[N+1];
		for(int i = 1; i <=N; ++i){
			ct[i] = Integer.parseInt(st.nextToken());
		}
		adj = new ArrayList[N+1];
		for(int i =1; i <=N; ++i)
			adj[i] = new ArrayList<Integer>();
		numcons = new int[N+1];
		for(int i = 1; i <= N-1; ++i){
			st = new StringTokenizer (br.readLine());
			int na = Integer.parseInt(st.nextToken());
			int nb = Integer.parseInt(st.nextToken());
			adj[na].add(nb);
			adj[nb].add(na);
			numcons[na]++;
			numcons[nb]++;
		}

		int cnt =0;
		for(int i =1; i <= N; ++i){
			int[] ctcp = ct.clone();
			int[] nccp = numcons.clone();
			fail = false;
			ArrayDeque<Integer> pq = new ArrayDeque<Integer>();
			pq.addLast(i);
			while(!fail && !pq.isEmpty()) {
				int na = pq.removeFirst();
				for(int nb: adj[na]) {
					if(fail)
						break;
					if(ctcp[nb] >= 12 && nccp[na] == 1) {
						fail =true;
						break;
					}
					if(ctcp[nb]<12) {
						ctcp[nb]++;
						pq.addLast(nb);
						break;
					}
				}
			}

			boolean isReach = true;
			for (int j=1; j<=N; ++j)
				if(ctcp[j] != 12)
					isReach = false;
			if(isReach)
				cnt++;
		}
		System.out.println(cnt);
	}
}