#include <iostream>
#include <algorithm>
using namespace std;
typedef long long ll;
const int MOD = 998244353;
const int MAXN = 100005;
ll ksm(ll a,ll b)
{
    ll t = 1;
    while(b){
        if(b&1)    t = t*a%MOD;
        a = a*a%MOD;
        b >>= 1;
    }
    return t%MOD;
}
ll a[MAXN];
/*
2
4 10
1 -2 3 -1

*/
ll b[5][MAXN]; 
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        ll n,m;
        scanf("%lld %lld",&n,&m);
        for(int i = 1;i <= n;i++)
        scanf("%lld",&a[i]);
         
        ll x = 0;
        int cnt = 0;
        while(x < m && cnt < 5)
        {
//            printf("---------%d-------------\n",cnt);
            for(int i = 1;i <= n && x < m;i++)
            {
                x += a[i];
                if(x < 0)    x = 0;
//                printf("%d%c",x," \n"[i == n]);
                b[cnt][i] = x;
            }
//            printf("---------%d-------------\n",cnt);
            cnt += 1;
        }
//        printf("%d\n",cnt);
//        continue;
        
        if(x >= m)
        printf("%d\n",cnt);
        else
        {
            int f = 0;
            for(int i = 1;i <= n;i++)
            if(b[3][i] != b[4][i])
            {
                f = 1;
                break;
            }
            if(!f)
            puts("-1");
            else
            {
                ll Max = b[4][1];
                for(int i = 1;i <= n;i++)
                Max = max(Max,b[4][i]);
                
                ll cha = Max - b[4][1];
                
                ll inv = b[4][n] - b[3][n];
                ll be = b[0][n];
//                ll ans = (m - be)/inv;
                ll cs = (m - be - a[1] - cha)/inv - 5;
                ll xx = cs*inv + be;
                while(xx < m)// && cnt < 3)
                {
//                    printf("---------%d-------------\n",cnt);
                    for(int i = 1;i <= n && xx < m;i++)
                    {
                        xx += a[i];
                        if(x < 0)    x = 0;
//                        printf("%d%c",x," \n"[i == n]);
        //                b[cnt][i] = x;
                    }
//                    printf("---------%d-------------\n",cnt);
                    cs += 1;
                }
                printf("%lld\n",cs + 1);
            }
        }
    }
    return 0;
}