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: /*
  stream Butter!
  eggyHide eggyVengeance
  I need U
  xiao rerun when
   */
  import static java.lang.Math.*;
  import java.util.*;
  import java.io.*;
  import java.math.*;
  
  public class x1622C
  {
      public static void main(String hi[]) throws Exception
      {
          BufferedReader infile = new BufferedReader(new InputStreamReader(System.in));
          StringTokenizer st = new StringTokenizer(infile.readLine());
          int T = Integer.parseInt(st.nextToken());
          StringBuilder sb = new StringBuilder();
          while(T-->0)
          {
              st = new StringTokenizer(infile.readLine());
              int N = Integer.parseInt(st.nextToken());
              long K = Long.parseLong(st.nextToken());
              int[] arr = readArr(N, infile, st);
              sort(arr);
              long sum = 0L;
              for(int x: arr)
                  sum += x;
              if(sum <= K)
              {
                  sb.append("0\n");
                  continue;
              }
              long suffix = 0L;
              long res = sum-K;
              for(int a=N-1; a > 0; a--)
              {
                  suffix += arr[a];
                  long low = arr[0]-(sum-K)/(N-a+1)-2;
                  long high = arr[0];
                  while(low != high)
                  {
                      long mid = (low+high+1)>>1;
                      long delta = (N-a+1)*mid-arr[0]-suffix;
                      if(sum+delta <= K)
                          low = mid;
                      else
                          high = mid-1;
                  }
                  res = min(res, N-a+(arr[0]-low));
              }
              sb.append(res+"\n");
          }
          System.out.print(sb);
      }
      public static int[] readArr(int N, BufferedReader infile, StringTokenizer st) throws Exception
      {
          int[] arr = new int[N];
          st = new StringTokenizer(infile.readLine());
          for(int i=0; i < N; i++)
              arr[i] = Integer.parseInt(st.nextToken());
          return arr;
      }
      public static void sort(int[] arr)
      {
          //because Arrays.sort() uses quicksort which is dumb
          //Collections.sort() uses merge sort
          ArrayList<Integer> ls = new ArrayList<Integer>();
          for(int x: arr)
              ls.add(x);
          Collections.sort(ls);
          for(int i=0; i < arr.length; i++)
              arr[i] = ls.get(i);
      }
  }