CherryTrees

import java.util.*;
import java.io.*;
public class CherryTree{

    static int n, c, k, counter = 0;
    static int[] cherries, weight;
    static ArrayList<LinkedList<Pair>> adj = new ArrayList<LinkedList<Pair>>();

    static void dfs(int n) {
        if(adj.get(n).size() == 0) {
            if(cherries[n] >= c && weight[n] <= k) {
                counter ++;
            }
            return;
        }
        for(Pair p : adj.get(n)) {
            int next = p.a;
            weight[next] += p.b;
            dfs(next);
            cherries[n] += cherries[next];
            weight[n] += weight[next];
        }
        if(n != 1 && cherries[n] >= c && weight[n] <= k) {
            counter ++;
        }
    }

    public static void main(String[] args) throws IOException{
        readLine();
        n = nextInt();
        c = nextInt();
        k = nextInt();

        for(int i = 0; i <= n; i ++) {
            adj.add(new LinkedList<Pair>());
        }
        cherries = new int[n + 1];
        weight = new int[n + 1];
        readLine();

        for(int i = 1; i <= n; i ++) {
            cherries[i] = nextInt();
        }

        for(int i = 0; i < n - 1; i ++) {
            readLine();
            adj.get(nextInt()).add(new Pair(nextInt(), nextInt()));
        }

        dfs(1);
        System.out.println(counter);
    }
    static BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    static StringTokenizer st;
    static void readLine() throws IOException{
        st = new StringTokenizer(in.readLine());
    }
    static int nextInt() {
        return Integer.parseInt(st.nextToken());
    }

    static class Pair{
        int a, b;
        Pair(int a, int b){
            this.a = a;
            this.b = b;
        }
    }
}