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.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.io.OutputStream;
  import java.util.Arrays;
  import java.io.IOException;
  import java.util.InputMismatchException;
  import java.util.Random;
  import java.io.InputStreamReader;
  import java.io.Writer;
  import java.io.BufferedReader;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   *
   * @author Nipuna Samarasekara
   */
  public class Main {
      public static void main(String[] args) {
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          FastScanner in = new FastScanner(inputStream);
          FastPrinter out = new FastPrinter(outputStream);
          TaskC solver = new TaskC();
          solver.solve(1, in, out);
          out.close();
      }
  
      static class TaskC {
          public void solve(int testNumber, FastScanner in, FastPrinter out) {
              int t = in.nextInt();
              while (t-- > 0) {
                  int n = in.nextInt();
                  long k = in.nextLong();
                  int[] a = in.readIntArray(n);
                  ru_ifmo_niyaz_arrayutils_ArrayUtils.sort(a);
                  long total = net_egork_misc_ArrayUtils.sumArray(a);
                  long diff = total - k;
                  int pos = n - 1;
                  long ct = 1;
                  int moves = 0;
                  while (diff > 0 && pos > 0) {
                      if (a[pos] - a[0] >= ct) {
                          diff -= a[pos] - a[0];
                          pos--;
                          ct++;
                      } else {
                          diff -= ct;
                          a[0]--;
                      }
                      moves++;
                  }
  
                  if (diff > 0) {
                      moves += (diff + ct - 1) / ct;
                  }
  
                  out.println(moves);
  
              }
          }
  
      }
  
      static class ru_ifmo_niyaz_arrayutils_ArrayUtils {
          static final long seed = System.nanoTime();
          static final Random rand = new Random(seed);
  
          public static void sort(int[] a) {
              shuffle(a);
              Arrays.sort(a);
          }
  
          public static void shuffle(int[] a) {
              for (int i = 0; i < a.length; i++) {
                  int j = rand.nextInt(i + 1);
                  int t = a[i];
                  a[i] = a[j];
                  a[j] = t;
              }
          }
  
      }
  
      static class FastPrinter extends PrintWriter {
          public FastPrinter(OutputStream out) {
              super(out);
          }
  
          public FastPrinter(Writer out) {
              super(out);
          }
  
      }
  
      static class net_egork_misc_ArrayUtils {
          public static long sumArray(int[] array) {
              long result = 0;
              for (int element : array)
                  result += element;
              return result;
          }
  
      }
  
      static class FastScanner extends BufferedReader {
          public FastScanner(InputStream is) {
              super(new InputStreamReader(is));
          }
  
          public int read() {
              try {
                  int ret = super.read();
                  //            if (isEOF && ret < 0) {
                  //                throw new InputMismatchException();
                  //            }
                  //            isEOF = ret == -1;
                  return ret;
              } catch (IOException e) {
                  throw new InputMismatchException();
              }
          }
  
          public String next() {
              StringBuilder sb = new StringBuilder();
              int c = read();
              while (isWhiteSpace(c)) {
                  c = read();
              }
              if (c < 0) {
                  return null;
              }
              while (c >= 0 && !isWhiteSpace(c)) {
                  sb.appendCodePoint(c);
                  c = read();
              }
              return sb.toString();
          }
  
          static boolean isWhiteSpace(int c) {
              return c >= 0 && c <= 32;
          }
  
          public int nextInt() {
              int c = read();
              while (isWhiteSpace(c)) {
                  c = read();
              }
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              int ret = 0;
              while (c >= 0 && !isWhiteSpace(c)) {
                  if (c < '0' || c > '9') {
                      throw new NumberFormatException("digit expected " + (char) c + " found");
                  }
                  ret = ret * 10 + c - '0';
                  c = read();
              }
              return ret * sgn;
          }
  
          public long nextLong() {
              return Long.parseLong(next());
          }
  
          public String readLine() {
              try {
                  return super.readLine();
              } catch (IOException e) {
                  return null;
              }
          }
  
          public int[] readIntArray(int n) {
              int[] ret = new int[n];
              for (int i = 0; i < n; i++) {
                  ret[i] = nextInt();
              }
              return ret;
          }
  
      }
  }
  
  