#include <bits/stdc++.h>

using namespace std;

using vi = vector<int>;
using graph = vector<vi>;
using ar = array<int, 3>;
const int INF = 1e9;

ar dfs(int u, int p, const graph & g, const vi & c, int k) {
    ar res = {c[u], 0, INF};
    for (int v : g[u]) {
        if (v == p) {
            continue;
        }
        auto [su, eaten, caneat] = dfs(v, u, g, c, k);
        res[0] += su;
        res[1] += eaten;
        res[2] = min(res[2], caneat);
    }
    if (res[0] >= k) {
        if (res[0] % 2 == k % 2 || res[0] - res[2] >= k) {
            return {0, res[1] + 1, INF};
        }
    }
    return res;
}

void solve() {
    int n, k;
    cin >> n >> k;
    vi c(n);
    for (int i = 0; i < n; ++i) {
        cin >> c[i];
    }
    graph g(n);
    for (int i = 0; i < n - 1; ++i) {
        int u, v;
        cin >> u >> v;
        --u;--v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    auto [_, ans, __] = dfs(0, 0, g, c, k);
    cout << ans << '\n';
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int t;
    cin >> t;
    while (t--) {
        solve();
    }
}