import java.io.BufferedReader;
import java.io.InputStreamReader;
class MeatBalls{
static int a[]=null;
static int n=0;
public static void main(String args[]) throws Exception{
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
int T=Integer.parseInt(br.readLine());
String s[]=null;
while(T>0){
s=br.readLine().split(" ");
n=Integer.parseInt(s[0]);
int m=Integer.parseInt(s[1]);
s=br.readLine().split(" ");
a=new int[n];
int sum=0;
for(int j=0;j<n;j++){
a[j]=Integer.parseInt(s[j]);
}
sort();
int i=0;
for(i=n-1 ;i>=0 && sum<m;i--){
sum=sum+a[i];
}
if(i<0 && sum<m)
System.out.println(-1);
else
System.out.println(n-1-i);
T--;
}
}
public static void sort(){
for(int i=0;i<n;i++){
for(int j=0;j<n-1-i;j++){
if(a[j+1]<a[j]){
int t=a[j];
a[j]=a[j+1];
a[j+1]=t;
}
}
}
}
}