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.*;
  import java.util.*;
  
  public class c {
      public static void main(String[] args) throws Exception {
          BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
          PrintWriter out = new PrintWriter(System.out);
          int numcases = Integer.parseInt(in.readLine());
          StringBuilder b = new StringBuilder();
          for (int casenum = 0; casenum < numcases; casenum++) {
              StringTokenizer tokenizer = new StringTokenizer(in.readLine());
              int n = Integer.parseInt(tokenizer.nextToken());
              long k = Long.parseLong(tokenizer.nextToken());
              long[] arr = new long[n];
              tokenizer = new StringTokenizer(in.readLine());
              long sum = 0;
              for (int i = 0; i < n; i++) {
                  sum += arr[i] = Integer.parseInt(tokenizer.nextToken());
              }
              ruffleSort(arr);
              long answer = Math.max(0, sum - k);
              //System.out.println(casenum + " answer init: " + answer);
              if (sum > k) {
                  long sum2 = 0;
                  int count = 1;
                  long val = sum - k;
                  for (int i = arr.length - 1; i > 0; i--) {
                      count++;
                      sum2 += arr[i] - arr[0];
                      answer = Math.min(answer, count - 1 + Math.max(0, (val - sum2 + count - 1) / count));
                  }
              }
              b.append(answer + "\n");
          }
          System.out.print(b);
          in.close();
          out.close();
      }
      static void ruffleSort(long[] a) {
          Random get = new Random();
          for (int i = 0; i < a.length; i++) {
              int r = get.nextInt(a.length);
              long temp = a[i];
              a[i] = a[r];
              a[r] = temp;
          }
          Arrays.sort(a);
      }
  }