#include <bits/stdc++.h>

using namespace std;

#define all(x) (x).begin(), (x).end()

void solve(int cs) {
  int n; int64_t s;
  cin >> n >> s;
  vector<int> a(n);
  for (int i = 0; i < n; i++) cin >> a[i];

  int hi = 1e9, lo = 1, ans = -1;
  while (hi >= lo) {
    int mid = hi + lo >> 1;
    int64_t ns = 0;
    for (auto &it : a) ns += it / mid;
    if (ns <= s) ans = mid, hi = mid - 1;
    else lo = mid + 1;
  }
  if (ans != -1) for (auto &it : a) s -= it / ans;
  cout << (s == 0 ? ans : -1) << "\n";
}

int32_t main() {
  cin.tie(0) -> sync_with_stdio(0);
  int t = 1;
  cin >> t;
  for (int i = 1; i <= t; i++) {
    solve(i);
  }
  return 0;
}