#include <stdio.h>//#include <bitsdc++.h>
#include <math.h>
#include <iostream>
#include <string.h>
#include <stdio.h>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <cstdio>
#define  MAX(x,y) (((x)>(y)) ? (x) : (y))
#define  MIN(x,y) (((x)<(y)) ? (x) : (y))
#define  sq(x) (x)*(x)
#define  cei(a,b) (long long)(((a)+(b)-1)/(b))
#define  mst(a,b) memset((a),b,sizeof((a)))
#define  fi first
#define  se second
#define  pb push_back
using namespace std;
const int MAXN = 1e6+5;
const int N=1e5+5;
const int E4=1e4;
//const long long mod = 1e9+7 ;
const long long mod = 998244353 ;
const int inf = 0x3f3f3f3f;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
int dx[4]= {1,0,0,-1};
int dy[4]= {0,-1,1,0};
ll a[N]= {0},sum[N];
ll n,m;
void solve()
{
    mst(sum,0);
    scanf("%lld%lld",&n,&m);
    int flag=0;
    for(int i=1; i<=n; i++)scanf("%lld",a+i);
    for(int i=1; i<=n; i++)sum[i]=sum[i-1]+a[i];
    ll maxadd=0,maxsub=0;
    for(int i=1; i<=n; i++) {
        maxadd=max(maxadd,sum[i]);
        maxsub=min(maxsub,sum[i]);
    }
    ll s=0,turn=1;
    for(int i=1; i<=n; i++) {
        s+=a[i];
        if(s<0)s=0;
        if(s>=m) {
            flag=1;
            break;
        }
    }
    if(!flag) {
        turn++;
        for(int i=1; i<=n; i++) {
            s+=a[i];
            if(s<0)s=0;
            if(s>=m) {
                flag=1;
                break;
            }
        }
    }
    int rc=0;
    if(!flag) {
        if(sum[n]<=0)turn=-1;
        else {
            while(1) {
                turn++;
                for(int i=1; i<=n; i++) {
                    s+=a[i];
                    if(s<0)s=0;
                    if(s>=m) {
                        flag=1;
                        break;
                    }

                }
                if(flag)break;
                if(s>=-maxsub) {
                    rc=1;
                    break;
                }
            }
            if(rc) {
                ll need=m-maxadd;
                ll times=cei(need-s,sum[n]);
//                printf("s %lld need %lld times %lld\n",s,need,times) ;
                turn+=times+1;
            }
        }
    }
    printf("%lld\n",turn);
}
int main()
{
    int T=1;
    scanf("%d",&T);
    for(int i=1; i<=T; i++) {
//        printf("Case %d:\n",i);
        solve();
    }
    return 0;
}