#include<bits/stdc++.h>
#ifdef xay5421
#define D(...) fprintf(stderr,__VA_ARGS__)
#define DD(...) D(#__VA_ARGS__ "="),debug_helper::debug(__VA_ARGS__),D("\n")
#include"/home/xay5421/debug.hpp"
#else
#define D(...) ((void)0)
#define DD(...) ((void)0)
#endif
#define pb push_back
#define eb emplace_back
#define SZ(x) ((int)(x).size())
#define each(x,v) for(auto&x:v)
#define rep(i,a,b) for(int i=(a);i<=(b);++i)
#define per(i,a,b) for(int i=(a);i>=(b);--i)
template<class T>void rd(T&x){int f=0,c;while(!isdigit(c=getchar()))f^=!(c^45);x=(c&15);while(isdigit(c=getchar()))x=x*10+(c&15);if(f)x=-x;}
template<class T>void pt(T x,int c=-1){if(x<0)putchar('-'),x=-x;if(x>9)pt(x/10);putchar(x%10+48);if(c!=-1)putchar(c);}
using namespace std;
using LL=long long;
using ULL=unsigned long long;
const int N=1000005,INF=0X3F3F3F3F;
int T,n,K,c[N];
vector<int>e[N];
int ans;
pair<int,int>dfs1(int k1,int k2){
	int v1=c[k1],v2=INF;
	for(auto&x:e[k1])if(x!=k2){
		auto [w1,w2]=dfs1(x,k1);
		v1+=w1,v2=min(v2,w2);
	}
	if(v1>=K&&(~(v1^K)&1)){
		++ans;
		return make_pair(0,INF);
	}else if(v1-v2>=K){
		++ans;
		return make_pair(0,INF);
	}else{
		if(v1&1)v2=min(v2,v1);
		return make_pair(v1,v2);
	}
}
int main(){
#ifdef xay5421
	freopen("a.in","r",stdin);
#endif
	rd(T);
	while(T--){
		rd(n),rd(K);
		rep(i,1,n)e[i].clear();
		rep(i,1,n)rd(c[i]);
		rep(i,2,n){
			int u,v;
			rd(u),rd(v);
			e[u].pb(v);
			e[v].pb(u);
		}
		ans=0;
		dfs1(1,0);
		printf("%d\n",ans);
	}
	return 0;
}