#include<bits/stdc++.h>

using namespace std;

const int maxn = 2e5+;

int a[maxn];

int head[maxn],nxt[maxn<<],to[maxn<<],ect;

inline void addEdge(int u,int v)

{

    to[ect] = v;

    nxt[ect] = head[u];

    head[u] = ect++;

}

int ct[maxn],m,cnt;

void dfs(int u,int f)

{

    if(a[u]) ct[u] = ct[f]+;

    if(ct[u]>m) return;

    int ch = ;

    for(int i = head[u]; ~i ; i = nxt[i]){

        int v = to[i];

        if(v == f) continue;

        ch++;

        dfs(v,u);

    }

    if(!ch) { cnt++; }

}

//#define LOCAL

int main()

{

#ifdef LOCAL

    freopen("in.txt","r",stdin);

#endif

    memset(head,-,sizeof(head));

    int n; scanf("%d%d",&n,&m);

    for(int i = ; i <= n; i++) scanf("%d",a+i);

    for(int i = ; i < n; i++){

        int u,v; scanf("%d%d",&u,&v);

        addEdge(u,v); addEdge(v,u);

    }

    dfs(,);

    printf("%d",cnt);

    return ;

}