#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int M=1e5+5;
int n,tes,id;
ll m,a[M*2],now,mx,ans;
void solve(){
    ans=now=mx=id=0;
    scanf("%d%lld",&n,&m);
    for(int i=1;i<=n;i++){scanf("%lld",&a[i]);a[i+n]=a[i];}
    for(int i=1;i<=n*2;i++){
        now+=a[i];
        if(now<0)now=0,id=i;
        mx=max(mx,now);
        if(mx>=m){printf("%d\n",(i-1)/n+1);return;}
    }
    now=mx=0;id=id%n;
    for(int i=id+1;i<=id+n;i++){
        now+=a[i];
        if(now<0){puts("-1");return;}
        mx=max(mx,now);
    }
    if(now<=0){puts("-1");return;}
    ans=((m-mx-1)/now+1);
    m=m-now*ans;
    for(int i=id+1;i<=id+n;i++){
        now+=a[i];
        if(now>=m){ans+=(i-1)/n;break;}
    }
    printf("%lld\n",ans+1);
}
int main()
{
    scanf("%d",&tes);
    while(tes--)solve();
    return 0;
}