#include <bits/stdc++.h>

using namespace std;

const int N = 1e5;
int n,m;
int ans;
vector<int>graph[N];
bool w[N];

void dfs (int v, int pr, int k){
    if (k>m){
        return;
    }
    int ok=1;
    for (auto to : graph[v]){
        if (to!=pr){
            ok=0;
            dfs(to,v,k*w[to]+w[to]);
        }
    }
    ans+=ok;
}

int main (){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    cin >> n >> m;
    for (int i=0; i<n; ++i){
        int t; cin >> t;
        w[i]=t;
    }
    for (int i=0; i<n-1; ++i){
        int v,u; cin >> v >> u;
        --v;
        --u;
        graph[v].push_back(u);
        graph[u].push_back(v);
    }
    dfs(0,-1,w[0]);
    cout << ans;
    return 0;
}