#include <bits/stdc++.h>
#define ll long long
using namespace std;
struct node{
    ll a;
    vector< node* > vec;
};

ll dfs(node* head, ll x){
    ll sum = head->a;
    for(auto i:head->vec){
        sum+=dfs(i,x);
    }
    return max((-1)*x, sum);
}
int main(){
    ll t,n,x,i,u,v,ans;
    cin>>t;
    while(t--){
        cin>>n>>x;
        node* tree[n+1];
        for(i=1;i<=n;i++){
            tree[i]=new node();
            cin>>tree[i]->a;
        }
        for(i=0;i<n-1;i++){
            cin>>u>>v;
            tree[u]->vec.push_back(tree[v]);
        }
        ans = dfs(tree[1], x);
        cout<<ans<<endl;
    }
}