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.util.Arrays;
  import java.util.Random;
  import java.util.StringTokenizer;
  
  public class SetOrDecrease {
  	
  	static class FastReader {
  		
          BufferedReader br;
          StringTokenizer st;
   
          public FastReader()
          {
              br = new BufferedReader(
                  new InputStreamReader(System.in));
          }
   
          String next()
          {
              while (st == null || !st.hasMoreElements()) {
                  try {
                      st = new StringTokenizer(br.readLine());
                  }
                  catch (IOException e) {
                      e.printStackTrace();
                  }
              }
              return st.nextToken();
          }
   
          int nextInt() { return Integer.parseInt(next()); }
   
          long nextLong() { return Long.parseLong(next()); }
          
          double nextFloat() { return Float.parseFloat(next()); }
   
          double nextDouble() { return Double.parseDouble(next()); }
   
          String nextLine()
          {
              String str = "";
              try {
                  str = br.readLine();
              }
              catch (IOException e) {
                  e.printStackTrace();
              }
              return str;
          }
          
          int[] nextArray(int n)
          {
          	int[] a = new int[n];
          	for (int i=0; i<n; i++) {
          		a[i] = this.nextInt();
          	}
          	return a;
          }
          
          long[] nextArrayLong(int n)
          {
          	long[] a = new long[n];
          	for (int i=0; i<n; i++) {
          		a[i] = this.nextLong();
          	}
          	return a;
          }
          
      }
  	
  	static final Random random=new Random();
  	public static void ruffleSort(int[] a)
  	{
          int n=a.length;
          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);
      }
  	
  	public static void solve(int n, long k, int[] a) {
  		
  		ruffleSort(a);
  		long sum = 0;
  		for (int val : a) {
  			sum += val;
  		}
  		if (sum <= k) {
  			System.out.println("0");
  			return;
  		}
  		if (n == 1) {
  			System.out.println(a[0] - k);
  			return;
  		}
  		sum = 0;
  		long ans = Long.MAX_VALUE;
  		for (int i=0; i<n; i++) {
  			if (i != 0) {
  				sum += a[i];
  			}
  			double temp = (double)(k - sum)/(n - i);
  			long c = (long)Math.ceil((double) a[0] - temp);
  			if (c < 0) {
  				c = 0;
  			}
  			ans = Math.min(ans, c + n - 1 - i);
  		}
  		System.out.println(ans);
  		
  	}
  
  	public static void main(String[] args) {
  		
  		FastReader in = new FastReader();
  		int t = in.nextInt();
  		while (t-- > 0) {
  			int n = in.nextInt();
  			long k = in.nextLong();
  			int[] a = in.nextArray(n);
  			solve(n, k, a);
  		}
  
  	}
  
  }
  