#include<iostream>
#include<cstring>
#include<vector>
#include<algorithm>
#define MAX_N 100005
using namespace std;

vector<int> G[MAX_N];
int n,m;
bool cat[MAX_N];

int ans=0;

void dfs(int u,int p,int c) {
    if (c > m)return;
    bool update = false;
    for (int i = 0; i < G[u].size(); i++) {
        int v = G[u][i];
        if (v == p)continue;
        update = true;
        dfs(v, u, cat[v] * (c + cat[v]));
    }
    if (!update)ans++;
}

int main(){
    cin.sync_with_stdio(false);
    cin>>n>>m;
    for(int i=1;i<=n;i++)
        cin>>cat[i];
    for(int i=0;i<n-1;i++){
        int x,y;
        cin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs(1,0,cat[1]);
    cout<<ans<<endl;
    return 0;
}