#include <bits/stdc++.h>
#define broken cerr << "running on " << __FUNCTION__ <<" "<< __LINE__ << endl
#define x first
#define y second
#define mp make_pair
#define sz(a) int((a).size())
#define par pair<int, int>
#define poly vector<int>
#define i64 long long
#define u64 unsigned long long
using namespace std;
const int N = 1e5 + 10;
int n, a[N];
i64 m;

int check(i64 &x) {
    for(int i = 1; i <= n; i++) {
        x = max(0ll, x + a[i]);
        if(x >= m) return 1;
    }
    return 0;
}

i64 solve() {
    cin >> n >> m;
    i64 sum = 0, mx = 0;
    for(int i = 1; i <= n; i++) cin >> a[i], sum += a[i], mx = max(mx, sum);
    i64 x = 0;
    if(check(x)) return 1;
    i64 y = x;
    if(check(x)) return 2;
    i64 z = x;
    if(y >= z) return -1;
    i64 d = z - y;
    return 1 + (m - y - mx + d - 1) / d + 1;
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    int T;
    cin >> T;
    while(T--) cout << solve() << endl;
    return 0;
}