Kefa decided to celebrate his first big salary by going to the restaurant. 

He lives by an unusual park. The park is a rooted tree consisting of n vertices with the root at vertex 1. Vertex 1 also contains Kefa's house. Unfortunaely for our hero, the park also contains cats. Kefa has already found out what are the vertices with cats in them.

The leaf vertices of the park contain restaurants. Kefa wants to choose a restaurant where he will go, but unfortunately he is very afraid of cats, so there is no way he will go to the restaurant if the path from the restaurant to his house contains more than m consecutive vertices with cats. 

Your task is to help Kefa count the number of restaurants where he can go.

Input

The first line contains two integers, n and m (2 ≤ n ≤ 105, 1 ≤ m ≤ n) — the number of vertices of the tree and the maximum number of consecutive vertices with cats that is still ok for Kefa.

The second line contains n integers a1, a2, ..., an, where each ai either equals to 0 (then vertex i has no cat), or equals to 1 (then vertex i has a cat).

Next n - 1 lines contains the edges of the tree in the format "xi yi" (without the quotes) (1 ≤ xi, yi ≤ n, xi ≠ yi), where xi and yi are the vertices of the tree, connected by an edge. 

It is guaranteed that the given set of edges specifies a tree.

Output

A single integer — the number of distinct leaves of a tree the path to which from Kefa's home contains at most m consecutive vertices with cats.

Examples

Input

4 1
1 1 0 0
1 2
1 3
1 4


Output

2


Input

7 1
1 0 1 1 0 0 0
1 2
1 3
2 4
2 5
3 6
3 7


Output

2

Note

Let us remind you that a tree is a connected graph on n vertices and n - 1 edge. A rooted tree is a tree with a special vertex called root. In a rooted tree among any two vertices connected by an edge, one vertex is a parent (the one closer to the root), and the other one is a child. A vertex is called a leaf, if it has no children.

Note to the first sample test: <image> The vertices containing cats are marked red. The restaurants are at vertices 2, 3, 4. Kefa can't go only to the restaurant located at vertex 2.

Note to the second sample test: <image> The restaurants are located at vertices 4, 5, 6, 7. Kefa can't go to restaurants 6, 7.
// package codeForces;

import java.util.*;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.io.*;
import java.math.*;
import java.text.*;

public class TKefaandPark {

	static InputReader in = new InputReader(System.in);
	static OutputWriter out = new OutputWriter(System.out);
	static int an=0;
	
	
	static int dfs(int s,ArrayList<ArrayList<Integer>> ar,boolean vis[],int arr[],int m,int k,int pre) {
		
		if(arr[s]+k>m)
			return 0;

		vis[s]=true;
		int ans=0;
		

		int ch=0;
		for(int j:ar.get(s)) {
			if(!vis[j]) {
			ch=1;
				if(arr[s]==1) {
					ans=ans+dfs(j,ar,vis,arr,m,k+1,s);
				}
				else {
					ans=ans+dfs(j,ar,vis,arr,m,0,s);
				}
				
			}
		}
//		System.out.println(ans);
		if(ch==0)
			return 1;
		return ans;
	}

	public static void main(String[] args) throws NumberFormatException, IOException {
		// TODO Auto-generated method stub
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int t = 1;
		while (t > 0) {

			int n=i();
			int m=i();
			int arr[]=new int[n+1];
			for(int i=1;i<=n;i++) {
				arr[i]=i();
			}
			ArrayList<ArrayList<Integer>> ar=new ArrayList(n+1);
			for(int i=0;i<=n;i++) {
				ar.add(new ArrayList<>());
			}
			int lf=0;
			for(int i=1;i<n;i++) {
				int a=i();
				int b=i();
				ar.get(a).add(b);
				ar.get(b).add(a);
			}
			for(int i=1;i<=n;i++) {
				if(ar.get(i).size()==0) {
					lf++;
				}
			}
//			System.out.println(ar);
			
			boolean vis[]=new boolean[n+1];
			System.out.println(dfs(1,ar,vis,arr,m,0,0));
			
			t--;
		}

		//		long l=l();
		//		String s=s();     //	ONLY BEFORE SPACE IN STRING , ELSE USE BUFFER-READER

	}

	public static long pow(long a, long b) {
		long m = 1000000007;
		long result = 1;
		while (b > 0) {
			if (b % 2 != 0) {
				result = (result * a) % m;
				b--;
			}
			a = (a * a) % m;
			b /= 2;
		}
		return result % m;
	}

	public static long gcd(long a, long b) {
		if (a == 0) {
			return b;
		}
		return gcd(b % a, a);
	}

	public static long lcm(long a, long b) {
		return a * (b / gcd(a, b));
	}

	public static long l() {
		String s = in.String();
		return Long.parseLong(s);
	}

	public static void pln(String value) {
		System.out.println(value);
	}

	public static int i() {
		return in.Int();
	}

	public static String s() {
		return in.String();
	}

}

class pair {
	int x, y;

	pair(int x, int y) {
		this.x = x;
		this.y = y;
	}
}

class CompareValue {

	static void compare(pair arr[], int n) {
		Arrays.sort(arr, new Comparator<pair>() {
			public int compare(pair p1, pair p2) {
				return p1.y - p2.y;
			}
		});
	}
}

class CompareKey {
	static void compare(pair arr[], int n) {
		Arrays.sort(arr, new Comparator<pair>() {
			public int compare(pair p1, pair p2) {
				return p2.x - p1.x;
			}
		});
	}
}

class InputReader {
	private InputStream stream;
	private byte[] buf = new byte[1024];
	private int curChar;
	private int numChars;
	private SpaceCharFilter filter;

	public InputReader(InputStream stream) {
		this.stream = stream;
	}

	public int read() {
		if (numChars == -1)
			throw new InputMismatchException();
		if (curChar >= numChars) {
			curChar = 0;
			try {
				numChars = stream.read(buf);
			} catch (IOException e) {
				throw new InputMismatchException();
			}
			if (numChars <= 0)
				return -1;
		}
		return buf[curChar++];
	}

	public int Int() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-') {
			sgn = -1;
			c = read();
		}
		int res = 0;
		do {
			if (c < '0' || c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(c));
		return res * sgn;
	}

	public String String() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do {
			res.appendCodePoint(c);
			c = read();
		} while (!isSpaceChar(c));
		return res.toString();
	}

	public boolean isSpaceChar(int c) {
		if (filter != null)
			return filter.isSpaceChar(c);
		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	}

	public String next() {
		return String();
	}

	public interface SpaceCharFilter {
		public boolean isSpaceChar(int ch);
	}

	public double readDouble() {
		int c = read();
		while (isSpaceChar(c)) {
			c = read();
		}
		int sgn = 1;
		if (c == '-') {
			sgn = -1;
			c = read();
		}
		double res = 0;
		while (!isSpaceChar(c) && c != '.') {
			if (c == 'e' || c == 'E') {
				return res * Math.pow(10, Int());
			}
			if (c < '0' || c > '9') {
				throw new InputMismatchException();
			}
			res *= 10;
			res += c - '0';
			c = read();
		}
		if (c == '.') {
			c = read();
			double m = 1;
			while (!isSpaceChar(c)) {
				if (c == 'e' || c == 'E') {
					return res * Math.pow(10, Int());
				}
				if (c < '0' || c > '9') {
					throw new InputMismatchException();
				}
				m /= 10;
				res += (c - '0') * m;
				c = read();
			}
		}
		return res * sgn;
	}
}

class OutputWriter {
	private final PrintWriter writer;

	public OutputWriter(OutputStream outputStream) {
		writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
	}

	public OutputWriter(Writer writer) {
		this.writer = new PrintWriter(writer);
	}

	public void print(Object... objects) {
		for (int i = 0; i < objects.length; i++) {
			if (i != 0) {
				writer.print(' ');
			}
			writer.print(objects[i]);
		}
		writer.flush();
	}

	public void printLine(Object... objects) {
		print(objects);
		writer.println();
		writer.flush();
	}

	public void close() {
		writer.close();
	}

	public void flush() {
		writer.flush();
	}
}

class IOUtils {
	public static int[] readIntArray(InputReader in, int size) {
		int[] array = new int[size];
		for (int i = 0; i < size; i++)
			array[i] = in.Int();
		return array;
	}
}

/**
 * TO SORT VIA TWO KEYS , HERE IT IS ACCORDING TO ASCENDING ORDER OF FIRST AND
 * DESC ORDER OF SECOND
 * LIST name-list 
 * ARRAYLIST
 * COPY PASTE
 * 
 * Collections.sort(list, (first,second) ->{
		    	if(first.con >second.con)
		    		return -1;
		    	else if(first.con<second.con)
		    		return 1;
		    	else {
		    		if(first.index >second.index)
		    			return 1;
		    		else
		    			return -1;
		    	}
		    	
		    });
 * 
 */

/**
 * 
 

  DECIMAL FORMATTER
Double k = in.readDouble();

System.out.println(k);
DecimalFormat df = new DecimalFormat("#.##");
System.out.print(df.format(k));
out.printLine(k);
* 
* */
