#include<bits/stdc++.h>
#define ll long long
using namespace std;
int T,n;
ll m,a[100005],sum,maxsum,L,H[100005],nw,MM[100005],Mn;
int fa[100005],A,fl;

ll read(){
    ll x=0,v=0;char ch=getchar();
    while(!isdigit(ch)) v|=(ch=='-'),ch=getchar();
    while(isdigit(ch)) x=(x<<3)+(x<<1)+(ch^48),ch=getchar();
    return v?-x:x;
}

void print(ll x){
    if(x>=10) print(x/10);
    putchar(x%10+'0');
}

int find(int x){
    if(x==fa[x]) return x;
    return fa[x]=find(fa[x]);
}

int main(){
    T=read();
    while(T--){
        n=read(),m=read();
        for(int i=1;i<=n;i++) a[i]=read(),fa[i]=i,H[i]=a[i];
        sum=maxsum=0,Mn=MM[0]=0;
        fl=0;
        for(int i=1;i<=n;i++){
            if(sum+a[i]<0) sum=0,fl=1;
            else{
                sum+=a[i];
                if(i>1&&!fl) fa[i-1]=i,H[i]+=H[i-1];
                fl=0;
            }
            maxsum=max(maxsum,sum);
            Mn+=a[i],MM[i]=max(MM[i-1],Mn);
        }
        maxsum=max(maxsum,sum);
        L=0,fl=0,nw=0;
        while(L<=3*n){
            L++;
            A=find(1);
            while(A<n){
                if(a[A+1]+H[find(1)]+nw>=0){
                    fa[A]=fa[find(A+1)],H[find(A+1)]+=H[A];
                    A=find(A+1);
                }
                else break;
            }
            if(nw+MM[find(1)]>=m||maxsum>=m){
                nw=max(nw+MM[find(1)],maxsum);
                fl=1;break;
            }
            if(find(1)==find(n)){
                L--;
                break;
            }
            nw=max(0ll,H[find(n)]);
        }
        if(find(1)!=find(n)&&!fl) puts("-1");
        else{
            if(nw>=m) print(L);
            else if(nw+MM[n]>=m) print(L+1);
            else{
                if(H[find(1)]!=0) print(L+(m-MM[n]-nw-1)/H[find(1)]+2);
                else printf("-1");
            }
            puts("");
        }
    }

    return 0;
}