#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll>PLL;
typedef pair<int, int>PII;
typedef pair<double, double>PDD;
#define I_int ll
inline ll read()
{
    ll x = 0, f = 1;
    char ch = getchar();
    while(ch < '0' || ch > '9')
    {
        if(ch == '-')f = -1;
        ch = getchar();
    }
    while(ch >= '0' && ch <= '9')
    {
        x = x * 10 + ch - '0';
        ch = getchar();
    }
    return x * f;
}
  
inline void out(ll x){
    if (x < 0) x = ~x + 1, putchar('-');
    if (x > 9) out(x / 10);
    putchar(x % 10 + '0');
}
  
inline void write(ll x){
    if (x < 0) x = ~x + 1, putchar('-');
    if (x > 9) write(x / 10);
    putchar(x % 10 + '0');
}
  
#define read read()
#define closeSync ios::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define multiCase int T;cin>>T;for(int t=1;t<=T;t++)
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define repp(i,a,b) for(int i=(a);i<(b);i++)
#define per(i,a,b) for(int i=(a);i>=(b);i--)
#define perr(i,a,b) for(int i=(a);i>(b);i--)
ll ksm(ll a, ll b,ll p)
{
    ll res = 1;
    while(b)
    {
        if(b & 1)res = res * a%p ;
        a = a * a %p;
        b >>= 1;
    }
    return res;
}

const int inf = 0x3f3f3f3f;
const int maxn=1e5+7,maxm=210000;

ll n,m,a[maxn];

int main(){
    int _=read;
    while(_--){
        n=read,m=read;
        ll sum=0,maxx=-inf;
        rep(i,1,n) a[i]=read,sum+=a[i],maxx=max(maxx,sum);
        ll x=0,res=0,lasx=0,cnt=0,lascnt=-1;
        while(1){
            rep(i,1,n){
                x=max(0ll,x+a[i]);
                if(x>=m) break;
            }
            res++;
            if(x>=m) break;
            cnt=x-lasx;
            if(lascnt==cnt) break;
            lascnt=cnt,lasx=x;
        }
        if(x>=m) printf("%lld\n",res);
        else{
            if(cnt==0){
                puts("-1");continue;
            }
            if(maxx==cnt){
                ll t=m-x;
                res+=t/cnt;
                if(t%cnt) res++;
                printf("%lld\n",res);
            }
            else{
                ll t=m-x-maxx;
                //cout<<t<<" "<<cnt<<" "<<res<<endl;
                res+=t/cnt+1;
                //cout<<t/cnt<<endl;
                if(t%cnt) res++;
                printf("%lld\n",res);
            }
        }
    }
    
    
    
    
    
    
    
    return 0;
}