description: You are given an integer array a_1, a_2, ..., a_n and integer k.
  
  In one step you can 
  
    * either choose some index i and decrease a_i by one (make a_i = a_i - 1); 
    * or choose two indices i and j and set a_i equal to a_j (make a_i = a_j). 
  
  
  
  What is the minimum number of steps you need to make the sum of array ∑_{i=1}^{n}{a_i} ≤ k? (You are allowed to make values of array negative).
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 10^4) — the number of test cases.
  
  The first line of each test case contains two integers n and k (1 ≤ n ≤ 2 ⋅ 10^5; 1 ≤ k ≤ 10^{15}) — the size of array a and upper bound on its sum.
  
  The second line of each test case contains n integers a_1, a_2, ..., a_n (1 ≤ a_i ≤ 10^9) — the array itself.
  
  It's guaranteed that the sum of n over all test cases doesn't exceed 2 ⋅ 10^5.
  
  Output
  
  For each test case, print one integer — the minimum number of steps to make ∑_{i=1}^{n}{a_i} ≤ k.
  
  Example
  
  Input
  
  
  4
  1 10
  20
  2 69
  6 9
  7 8
  1 2 1 3 1 2 1
  10 1
  1 2 3 1 2 6 1 6 8 10
  
  
  Output
  
  
  10
  0
  2
  7
  
  Note
  
  In the first test case, you should decrease a_1 10 times to get the sum lower or equal to k = 10.
  
  In the second test case, the sum of array a is already less or equal to 69, so you don't need to change it.
  
  In the third test case, you can, for example: 
  
    1. set a_4 = a_3 = 1; 
    2. decrease a_4 by one, and get a_4 = 0. 
  
  As a result, you'll get array [1, 2, 1, 0, 1, 2, 1] with sum less or equal to 8 in 1 + 1 = 2 steps.
  
  In the fourth test case, you can, for example: 
  
    1. choose a_7 and decrease in by one 3 times; you'll get a_7 = -2; 
    2. choose 4 elements a_6, a_8, a_9 and a_{10} and them equal to a_7 = -2. 
  
  As a result, you'll get array [1, 2, 3, 1, 2, -2, -2, -2, -2, -2] with sum less or equal to 1 in 3 + 4 = 7 steps.
solution: import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.Random;
  import java.util.StringTokenizer;
  
  /*
  
   */
  public class C {
  
  	
  	public static void main(String[] args) {
  		FastScanner fs=new FastScanner();
  		PrintWriter out=new PrintWriter(System.out);
  		int T=fs.nextInt();
  		for (int tt=0; tt<T; tt++) {
  			int n=fs.nextInt();
  			long maxSum=fs.nextLong();
  			int[] a=fs.readArray(n);
  			ruffleSort(a);
  			long[] cs=new long[n+1];
  			for (int i=1; i<=n; i++) cs[i]=cs[i-1]+a[i-1];
  			long ans=Long.MAX_VALUE;
  			for (int setToMin=1; setToMin<=n; setToMin++) {
  				int nEqualToMin=setToMin-1;
  				long subbed=cs[n]-cs[n-nEqualToMin]-a[0]*(long)(nEqualToMin);
  				long stillNeed=(cs[n]-subbed-maxSum);
  				stillNeed=Math.max(stillNeed, 0);
  				long turns=(setToMin-1) + (stillNeed +setToMin-1)/setToMin;
  				ans=Math.min(ans, turns);
  			}
  //			ans=Math.max(ans, 0);
  			out.println(ans);
  		}
  		out.close();
  	}
  	
  	static final Random random=new Random();
  	static final int mod=1_000_000_007;
  	
  	static void ruffleSort(int[] a) {
  		int n=a.length;//shuffle, then sort 
  		for (int i=0; i<n; i++) {
  			int oi=random.nextInt(n), temp=a[oi];
  			a[oi]=a[i]; a[i]=temp;
  		}
  		Arrays.sort(a);
  	}
  	static long add(long a, long b) {
  		return (a+b)%mod;
  	}
  	static long sub(long a, long b) {
  		return ((a-b)%mod+mod)%mod;
  	}
  	static long mul(long a, long b) {
  		return (a*b)%mod;
  	}
  	
  	static void sort(int[] a) {
  		ArrayList<Integer> l=new ArrayList<>();
  		for (int i:a) l.add(i);
  		Collections.sort(l);
  		for (int i=0; i<a.length; i++) a[i]=l.get(i);
  	}
  	
  	
  	static class FastScanner {
  		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
  		StringTokenizer st=new StringTokenizer("");
  		String next() {
  			while (!st.hasMoreTokens())
  				try {
  					st=new StringTokenizer(br.readLine());
  				} catch (IOException e) {
  					e.printStackTrace();
  				}
  			return st.nextToken();
  		}
  		
  		int nextInt() {
  			return Integer.parseInt(next());
  		}
  		int[] readArray(int n) {
  			int[] a=new int[n];
  			for (int i=0; i<n; i++) a[i]=nextInt();
  			return a;
  		}
  		long nextLong() {
  			return Long.parseLong(next());
  		}
  	}
  
  	
  }
  