#include <bits/stdc++.h>
#define mp make_pair
#define fi first
#define se second
#define debug(x) cerr << #x << " = " << (x) << endl
#define EPS 1e-9
#define PI acos(-1.0)
using namespace std;
void test() { cerr << endl; }
template <typename T, typename... Args>
void test(T x, Args... args) {
  cerr << x << " ";
  test(args...);
}
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int MAXN = (int)1e5 + 10;
const int MOD = 998244353;
const int INF = 1e9;
ll a[MAXN], sum[MAXN];
void Main() {
  int n; ll m;
  cin >> n >> m;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    sum[i] = sum[i-1] + a[i];
  }
  auto cal = [&](ll x) {
    if (x >= m) return 0;
    for (int i = 1; i <= n; i++){
      x = max(0ll, x + a[i]);
      if (x >= m) return i;
    }
    return -1;
  };
  ll l = 0, r = m, st = r;
  while (l <= r) {
    ll mid = (l + r) / 2;
    if (cal(mid) != -1) {
      st = mid;
      r = mid - 1;
    } else {
      l = mid + 1;
    }
  }
  ll ans = -1;
  if (st == 0) {
    ans = 1;
  } else {
    ll mi = *min_element(sum + 1, sum + 1 + n);
    if (mi < 0) {
      ll tmp = sum[n] - mi;
      if (tmp >= st) {
        ans = 1 + (cal(tmp) > 0);
      } else {
        if (tmp + mi > 0) {
          ll ti = (st - tmp + sum[n] - 1) / sum[n];
          ans = 1 + ti + (cal(tmp + ti * sum[n]) > 0);
        }
      }
    } else {
      ll ti = (st + sum[n] - 1) / sum[n];
      ans = ti + (cal(ti * sum[n]) > 0);
    }
  }
  cout << ans << "\n";
}
int main() {
  #ifdef BanFcc
    freopen("in.txt", "r", stdin);
  ///  freopen("out.txt", "w", stdout);
  #else
    ios_base:: sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cout << fixed << setprecision(10);
  #endif
  int T = 1;
  cin >> T;
  for (int ca = 1; ca <= T; ca++) {
   // cout << "Case #" << ca << ": ";
    Main();
  }
  return 0;
}