#include<bits/stdc++.h>
#define int long long
using namespace std;

void read(int &data){
    int x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){
        if(ch=='-') f=f*-1;
        ch=getchar();
    }
    while(ch>='0'&&ch<='9'){
        x=x*10+ch-'0';
        ch=getchar();
    }
    data=x*f;
}

void write(int x){
    if(x>10) write(x/10);
    putchar(x%10);
}

int t,n,m,x,tmp,a[100005],sm[100005];
int mx,mi,flag,ans;

signed main(){
    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    cin>>t;
    while(t--){
        cin>>n>>m;
        sm[0]=0;mi=1,mx=1,flag=0;
        flag=0;x=0;ans=0;
        for(int i=1;i<=n;i++){ 
            cin>>a[i];
            sm[i]=sm[i-1]+a[i]; //累计增长 
            if(sm[i]<sm[mi]) mi=i; //找到最小值 
            if(sm[i]>sm[mx]) mx=i; //找到最大值 
            if(x<0) x=0; //立刻变回0 
            x+=a[i];
            if(x>=m) ans=1;
        }
        if(ans){ //一轮游的情况 
            cout<<1<<endl;
            continue;
        }
        for(int i=1;i<=n;i++){
            if(x<0) x=0;
            x+=a[i];
            if(x>=m){
                flag=1;
                break; 
            }
        }
        if(flag){
            cout<<2<<endl;  //两轮游
            continue;
        }
        if(sm[n]<=0){ //先试两轮，再判断负增长 
            cout<<-1<<endl;
            continue;
        }
        //接下来是正增长
        ans=2+(m-x-sm[mx])/sm[n]; //算上前面的两轮游 
        x+=sm[n]*(ans-2);
        while(x<m){
            for(int i=1;i<=n;i++){
                x+=a[i];
                if(x>=m) break; 
            }
            ans++;
        }
        cout<<ans<<endl;
    }
    return 0;
}