#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;

typedef long long ll;

const int N = 1e5 + 100;

int n; ll m;
int sa[N];

ll cal(ll x) {
    for (int i = 1; i <= n; i++) {
        x += sa[i];
        if (x >= m) return x;
        if (x < 0) x = 0;
    }
    return x;
}

ll solve() {
    ll ma = 0, sum = 0;
    for (int i = 1; i <= n; i++) {
        sum += sa[i];
        ma = max(ma, sum);
    }
    ll r1 = cal(0);
    if (r1 >= m) return 1;
    ll r2 = cal(r1);
    if (r2 >= m) return 2;
    if (r1 == r2) return -1;
    ll r3 = cal(r2);
    if (r3 >= m) return 3;
    m -= r2 + ma;
    r3 -= r2;
    if (m % r3 == 0) return m / r3 + 3;
    return m / r3 + 4;
}

int main() {
    //freopen("0.txt", "r", stdin);
    int T; scanf("%d", &T);
    while (T--) {
        scanf("%d%lld", &n, &m);
        for (int i = 1; i <= n; i++) scanf("%d", sa + i);
        printf("%lld\n", solve());
    }
    return 0;
}