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 static java.lang.Math.*;
  import java.util.*;
  import java.io.*;
  
  public class Solution {
      public static long find(int n, long k, int[] a) {
          sort(a);
          long[] suff = new long[n];
          suff[n-1] = a[n-1];
          for (int i = n-2; i >= 0; i--) {
             suff[i] = suff[i+1] + a[i];
          }
          long sum = 0;
          for (int i: a) sum+= i;
          if (sum <= k) return 0;
          long req = sum-k;
  //        System.out.println("sum: " + sum);
  //        System.out.println("req: " + req);
          long res = req;
          for (int i = 1; i < n; i++) {
              long num = req - suff[n-i] + (long) i * a[0];
              if (num <= 0) {
                  res = min(res, i);
                  continue;
              }
              long den = i + 1;
              long x = (long) ceil((double) num/ (double) den);
  //            System.out.println("num: " + num);
  //            System.out.println("den: " + den);
  //            System.out.println("x: " + x);
  //            System.out.println("y: " + i);
              res = min(res, x + i);
          }
          return res;
      }
      public static void sort(int[] a) {
          ArrayList<Integer> al = new ArrayList<>();
          for (int i: a) al.add(i);
          Collections.sort(al);
          for (int i = 0; i < a.length; i++) {
              a[i] = al.get(i);
          }
      }
      public static void main(String[] args) {
          InputReader fs = new InputReader(System.in);
          PrintWriter pw = new PrintWriter(System.out);
          int t = fs.readInt();
          for (int tt = 0; tt < t; tt++) {
              int n = fs.readInt();
              long k = fs.readLong();
              int[] a = fs.readIntArray(n);
              pw.println(find(n, k, a));
          }
  
          pw.flush();
          pw.close();
      }
      static class InputReader
      {
          private InputStream stream;
          private byte[] buf = new byte[1024];
          private int curChar;
          private int numChars;
          private SpaceCharFilter filter;
  
          public InputReader(InputStream stream)
          {
              this.stream = stream;
          }
  
          public int read() {
              if (numChars == -1)
                  throw new InputMismatchException();
              if (curChar >= numChars)
              {
                  curChar = 0;
                  try
                  {
                      numChars = stream.read(buf);
                  }
                  catch (IOException e)
                  {
                      throw new InputMismatchException();
                  }
                  if (numChars <= 0)
                      return -1;
              }
              return buf[curChar++];
          }
  
          public int readInt() {
              int c = read();
              while (isSpaceChar(c))
                  c = read();
              int sgn = 1;
              if (c == '-')
              {
                  sgn = -1;
                  c = read();
              }
              int res = 0;
              do
              {
                  if (c < '0' || c > '9')
                      throw new InputMismatchException();
                  res *= 10;
                  res += c - '0';
                  c = read();
              } while (!isSpaceChar(c));
              return res * sgn;
          }
  
          public String readString() {
              int c = read();
              while (isSpaceChar(c))
                  c = read();
              StringBuilder res = new StringBuilder();
              do
              {
                  res.appendCodePoint(c);
                  c = read();
              } while (!isSpaceChar(c));
              return res.toString();
          }
  
          public double readDouble() {
              int c = read();
              while (isSpaceChar(c))
                  c = read();
              int sgn = 1;
              if (c == '-')
              {
                  sgn = -1;
                  c = read();
              }
              double res = 0;
              while (!isSpaceChar(c) && c != '.')
              {
                  if (c == 'e' || c == 'E')
                      return res * Math.pow(10, readInt());
                  if (c < '0' || c > '9')
                      throw new InputMismatchException();
                  res *= 10;
                  res += c - '0';
                  c = read();
              }
              if (c == '.')
              {
                  c = read();
                  double m = 1;
                  while (!isSpaceChar(c))
                  {
                      if (c == 'e' || c == 'E')
                          return res * Math.pow(10, readInt());
                      if (c < '0' || c > '9')
                          throw new InputMismatchException();
                      m /= 10;
                      res += (c - '0') * m;
                      c = read();
                  }
              }
              return res * sgn;
          }
  
          public long readLong() {
              int c = read();
              while (isSpaceChar(c))
                  c = read();
              int sgn = 1;
              if (c == '-')
              {
                  sgn = -1;
                  c = read();
              }
              long res = 0;
              do
              {
                  if (c < '0' || c > '9')
                      throw new InputMismatchException();
                  res *= 10;
                  res += c - '0';
                  c = read();
              } while (!isSpaceChar(c));
              return res * sgn;
          }
  
          public boolean isSpaceChar(int c) {
              if (filter != null)
                  return filter.isSpaceChar(c);
              return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
          }
          public int[] readIntArray(int n) {
              int[] a = new int[n];
              for (int i = 0; i < n; i++) {
                  a[i] = readInt();
              }
              return a;
          }
          public int[] readIntArrayShifted(int n) {
              int[] a = new int[n + 1];
              for (int i = 0; i < n; i++) {
                  a[i + 1] = readInt();
              }
              return a;
          }
          public long[] readLongArray(int n) {
              long[] a = new long[n];
              for (int i = 0; i < n; i++) {
                  a[i] = readLong();
              }
              return a;
          }
          public String next() {
              return readString();
          }
  
          interface SpaceCharFilter {
              public boolean isSpaceChar(int ch);
          }
      }
  
  }