#include <bits/stdc++.h>
using namespace std;
template <typename A, typename B>
string to_string(pair<A, B> p);
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);
string to_string(const string& s) { return '"' + s + '"'; }
string to_string(const char* s) { return to_string((string)s); }
string to_string(bool b) { return (b ? "true" : "false"); }
string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}
template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}
template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto& x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
using ll = long long;
using PII = pair<int, int>;
using PIL = pair<int, ll>;
int bs_biggest(int l, int r, const function<bool(int)>& check) {
  assert(l <= r);
  while (l < r) {
    int mid = (l + r + 1) / 2;
    if (check(mid))
      l = mid;
    else
      r = mid - 1;
  }
  return l;
}
int bs_smallest(int l, int r, const function<bool(int)>& check) {
  assert(l <= r);
  while (l < r) {
    int mid = (l + r) / 2;
    if (check(mid))
      r = mid;
    else
      l = mid + 1;
  }
  return l;
}
const int MOD = (int)1e9 + 7;
int fexp(int a, int b) {
  int res = 1;
  for (int i = 1; i <= b; i <<= 1) {
    if (i & b) res = (ll)res * a % MOD;
    a = (ll)a * a % MOD;
  }
  return res;
}
int inv(int first) { return fexp(first, MOD - 2); }
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
void my_main() {
  int T;
  cin >> T;
  while (T--) {
    int n, m;
    cin >> n >> m;
    auto b = vector<int>(n + 1);
    auto w = vector<int>(n + 1);
    for (int i = (1), i_end_ = (n + 1); i < i_end_; ++i) cin >> b[i];
    for (int i = (1), i_end_ = (n + 1); i < i_end_; ++i) cin >> w[i];
    vector<PII> edges;
    for (int i = (0), i_end_ = (n - 1); i < i_end_; ++i) {
      int first, second;
      cin >> first >> second;
      edges.push_back(make_pair(first, second));
    }
    auto fa = vector<int>(n + 1);
    auto good = vector<int>(n + 1);
    auto wsum = vector<ll>(n + 1);
    auto bsum = vector<ll>(n + 1);
    vector<vector<int>> S(n + 1);
    for (int i = (1), i_end_ = (n + 1); i < i_end_; ++i) {
      fa[i] = i;
      wsum[i] = w[i];
      bsum[i] = b[i];
      good[i] = (wsum[i] > bsum[i]);
      S[i].push_back(i);
    }
    auto merge = [&](int first, int second) -> void {
      assert(first != second);
      if (((int)S[first].size()) > ((int)S[second].size())) swap(first, second);
      for (auto e : S[first]) {
        fa[e] = second;
        wsum[second] += w[e];
        bsum[second] += b[e];
        S[second].push_back(e);
      }
      good[second] = (wsum[second] > bsum[second]);
      S[first].clear();
      wsum[first] = bsum[first] = good[first] = 0;
    };
    for (int fuck = (0), fuck_end_ = (n - m); fuck < fuck_end_; ++fuck) {
      bool done = false;
      for (auto e : edges) {
        int first = e.first, second = e.second;
        first = fa[first], second = fa[second];
        if (first == second) continue;
        if (good[first] != good[second]) {
          if (wsum[first] + wsum[second] > bsum[first] + bsum[second]) {
            merge(first, second);
            done = true;
            break;
          }
        }
      }
      if (done) continue;
      for (auto e : edges) {
        int first = e.first, second = e.second;
        first = fa[first], second = fa[second];
        if (first == second) continue;
        if (!good[first] && !good[second]) {
          merge(first, second);
          done = true;
          break;
        }
      }
      if (done) continue;
      for (auto e : edges) {
        int first = e.first, second = e.second;
        first = fa[first], second = fa[second];
        if (first == second) continue;
        if (good[first] && good[second]) {
          merge(first, second);
          done = true;
          break;
        }
      }
      if (done) continue;
      for (auto e : edges) {
        int first = e.first, second = e.second;
        first = fa[first], second = fa[second];
        if (first == second) continue;
        merge(first, second);
        done = true;
        break;
      }
      assert(done);
    }
    int ans = 0;
    for (int i = (1), i_end_ = (n + 1); i < i_end_; ++i)
      if (good[i]) ++ans;
    cout << ans << "\n";
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed << setprecision(12);
  my_main();
  return 0;
}
