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.Arrays;
  import java.util.InputMismatchException;
  
  public class C {
      public static void main(String[] args) {
          FastIO io = new FastIO();
          int t = io.nextInt();
          while (t-- > 0) {
              int n = io.nextInt();
              long k = io.nextLong();
              int[] arr = new int[n];
              for (int i = 0; i < n; i++) {
                  arr[i] = io.nextInt();
              }
              sort(arr);
              long sum = 0;
              long min = (long) 1e18;
              for (int iKeep = 0; iKeep < n; iKeep++) {
                  if (iKeep > 0)
                      sum += arr[iKeep];
                  long requiredSum = k - sum;
                  long required = (k - sum) / (n - iKeep);
  
                  if (requiredSum < 0 && requiredSum % (n - iKeep) != 0) required--;
                  long steps = Math.max(arr[0] - required, 0) + (n - iKeep - 1);
                  min = Math.min(steps, min);
              }
  
              io.println(min);
  
          }
          io.flush();
      }
  
      static void sort(int[] a) {
          Integer[] l = new Integer[a.length];
          for (int i = 0; i < a.length; i++) l[i] = a[i];
          Arrays.sort(l);
          for (int i = 0; i < a.length; i++) a[i] = l[i];
      }
  
      private static class FastIO extends PrintWriter {
          private InputStream stream;
          private byte[] buf = new byte[1 << 16];
          private int curChar, numChars;
  
          // standard input
          public FastIO() {
              this(System.in, System.out);
          }
  
          public FastIO(InputStream i, OutputStream o) {
              super(o);
              stream = i;
          }
  
          // file input
          public FastIO(String i, String o) throws IOException {
              super(new FileWriter(o));
              stream = new FileInputStream(i);
          }
  
          // throws InputMismatchException() if previously detected end of file
          private int nextByte() {
              if (numChars == -1) throw new InputMismatchException();
              if (curChar >= numChars) {
                  curChar = 0;
                  try {
                      numChars = stream.read(buf);
                  } catch (IOException e) {
                      throw new InputMismatchException();
                  }
                  if (numChars == -1) return -1; // end of file
              }
              return buf[curChar++];
          }
  
          // to read in entire lines, replace c <= ' '
          // with a function that checks whether c is a line break
          public String next() {
              int c;
              do {
                  c = nextByte();
              } while (c <= ' ');
              StringBuilder res = new StringBuilder();
              do {
                  res.appendCodePoint(c);
                  c = nextByte();
              } while (c > ' ');
              return res.toString();
          }
  
          public int nextInt() { // nextLong() would be implemented similarly
              int c;
              do {
                  c = nextByte();
              } while (c <= ' ');
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = nextByte();
              }
              int res = 0;
              do {
                  if (c < '0' || c > '9')
                      throw new InputMismatchException();
                  res = 10 * res + c - '0';
                  c = nextByte();
              } while (c > ' ');
              return res * sgn;
          }
  
          public long nextLong() { // nextLong() would be implemented similarly
              int c;
              do {
                  c = nextByte();
              } while (c <= ' ');
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = nextByte();
              }
              long res = 0;
              do {
                  if (c < '0' || c > '9')
                      throw new InputMismatchException();
                  res = 10 * res + c - '0';
                  c = nextByte();
              } while (c > ' ');
              return res * sgn;
          }
  
          public double nextDouble() {
              return Double.parseDouble(next());
          }
      }
  
  }
  