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.*;
  import java.util.concurrent.ThreadLocalRandom;
  
  public class A {
      private static void sport(int[] a, long k) {
          shuffleArray(a);
          Arrays.sort(a);
          int n = a.length;
          long ans=Long.MAX_VALUE;
          long[] p = new long[n+1];
          for (int i = 1; i <= n; i++) {
              p[i]=(long) p[i-1]+a[i-1];
          }
          if (p[n]<=k){
              System.out.println(0);
              return;
          }
          if (a.length == 1) {
              System.out.println(a[0] - k);
              return;
          }
          //x*(i+1)<=target
          long target = p[n]-k;
          for (int i = 1; i < n; i++) {
              target-=(long) (a[n-i]-a[0]);
              if (target<=0){
                  ans=Math.min(ans, i);
                  break;
              }
              long res = (long) target/(i+1);
              if (target%(i+1)!=0){
                  res++;
              }
              ans=Math.min(ans,res+i);
          }
          ans = Math.min(ans,p[n]-k);
          System.out.println(Math.max(0,ans));
      }
  
      public static void main(String[] args) throws IOException {
          FastScanner sc = new FastScanner();
          int t = sc.nextInt();
          for (int i = 0; i < t; i++) {
              int n = sc.nextInt();
              long k = sc.nextLong();
              int[] a = sc.readArrayInt(n);
              sport(a, k);
          }
      }
  
      static void shuffleArray(int[] ar) {
          // If running on Java 6 or older, use `new Random()` on RHS here
          Random rnd = ThreadLocalRandom.current();
          for (int i = ar.length - 1; i > 0; i--) {
              int index = rnd.nextInt(i + 1);
              // Simple swap
              int a = ar[index];
              ar[index] = ar[i];
              ar[i] = a;
          }
      }
  
      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());
          }
  
          void nextLine() throws IOException {
              br.readLine();
          }
  
          long[] readArrayLong(int n) {
              long[] a = new long[n];
              for (int i = 0; i < n; i++) {
                  a[i] = nextLong();
              }
              return a;
          }
  
          int[] readArrayInt(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());
          }
  
          double nextDouble() {
              return Double.parseDouble(next());
          }
      }
  }