#include <bits/stdc++.h>
using namespace std;
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T>
void __print(const T &x) {
  int f = 0;
  cerr << '{';
  for (auto &i : x) cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
struct val {
  long long nleaves, w;
  val() { nleaves = 0, w = 0; }
  val(long long l, long long wt) {
    nleaves = l;
    w = wt;
  }
  bool operator<(const val &b) const {
    return nleaves * (w - w / 2) < b.nleaves * (b.w - b.w / 2);
  }
};
void solve() {
  int n;
  cin >> n;
  ;
  long long S;
  cin >> S;
  ;
  vector<vector<pair<int, int> > > gr(n + 1);
  for (int i = 1; i <= n - 1; i++) {
    int u, v, w;
    cin >> u >> v >> w;
    ;
    gr[u].push_back({w, v});
    gr[v].push_back({w, u});
  }
  vector<int> dp(n + 1, 0);
  long long glsum = 0;
  multiset<val> m;
  function<void(int, int, long long)> dfs = [&](int u, int parent,
                                                long long sum) {
    dp[u] = 0;
    if (gr[u].size() == 1) {
      glsum += sum;
      dp[u] = 1;
    }
    for (auto &v : gr[u]) {
      if (v.second == parent) continue;
      dfs(v.second, u, sum + v.first);
      dp[u] += dp[v.second];
      m.insert(val(dp[v.second], v.first));
    }
    return;
  };
  dfs(1, -1, 0);
  int move = 0;
  val maxi;
  while (glsum > S) {
    auto it = m.rbegin();
    maxi = *it;
    glsum -= (maxi.w - maxi.w / 2) * maxi.nleaves;
    move++;
    auto it2 = --m.end();
    m.erase(it2);
    m.insert(val(maxi.nleaves, maxi.w / 2));
  }
  cout << move << endl;
  return;
}
int main() {
  int t;
  cin >> t;
  ;
  while (t--) solve();
  return 0;
}
