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.util.*;
  import java.io.*;
  
  public class Main {
      static FastScanner sc = new FastScanner(System.in);
      static PrintWriter pw = new PrintWriter(System.out);
      static StringBuilder sb = new StringBuilder();
      static long mod = (long) 1e9 + 7;
  
      public static void main(String[] args) throws Exception {
          int n = sc.nextInt();
          for(int i = 0; i < n; i++) solve();
          pw.flush();
      }
  
      public static void solve() {
          int n = sc.nextInt();
          long k = sc.nextLong();
          ArrayList<Long> a = new ArrayList<>();
          long total = 0;
          for(int i = 0; i < n; i++){
              long v = sc.nextLong();
              a.add(v);
              total += v;
          }
          Collections.sort(a);
          long a1 = a.get(0);
          long deg = total - k;
          if(deg <= 0){
              pw.println(0);
              return;
          }
          long ans = deg;
          long nextDeg = deg;
          for(int i = n-1; i > 0; i--){
              long tmp = n-i;
              long deg1 = nextDeg-a.get(i)+a1;
              //pw.println(deg1);
              if(deg1 <= 0){
                  ans = Math.min(ans,tmp);
                  break;
              }else{
                  long pow = n-i+1;
                  long rem1 = (deg1+pow-1)/pow;
                  ans = Math.min(ans,tmp+rem1);
              }
              nextDeg -= (a.get(i)-a1);
          }
          long max = k/(long)n;
          ans = Math.min(ans,Math.max(0,a1-max) + (n-1));
          pw.println(ans);
      }
      
      static class GeekInteger {
          public static void save_sort(int[] array) {
              shuffle(array);
              Arrays.sort(array);
          }
  
          public static int[] shuffle(int[] array) {
              int n = array.length;
              Random random = new Random();
              for (int i = 0, j; i < n; i++) {
                  j = i + random.nextInt(n - i);
                  int randomElement = array[j];
                  array[j] = array[i];
                  array[i] = randomElement;
              }
              return array;
          }
  
          public static void save_sort(long[] array) {
              shuffle(array);
              Arrays.sort(array);
          }
  
          public static long[] shuffle(long[] array) {
              int n = array.length;
              Random random = new Random();
              for (int i = 0, j; i < n; i++) {
                  j = i + random.nextInt(n - i);
                  long randomElement = array[j];
                  array[j] = array[i];
                  array[i] = randomElement;
              }
              return array;
          }
  
      }
  }
  
  
  
  class FastScanner {
      private BufferedReader reader = null;
      private StringTokenizer tokenizer = null;
  
      public FastScanner(InputStream in) {
          reader = new BufferedReader(new InputStreamReader(in));
          tokenizer = null;
      }
  
      public FastScanner(FileReader in) {
          reader = new BufferedReader(in);
          tokenizer = null;
      }
  
      public String next() {
          if (tokenizer == null || !tokenizer.hasMoreTokens()) {
              try {
                  tokenizer = new StringTokenizer(reader.readLine());
              } catch (IOException e) {
                  throw new RuntimeException(e);
              }
          }
          return tokenizer.nextToken();
      }
  
      public String nextLine() {
          if (tokenizer == null || !tokenizer.hasMoreTokens()) {
              try {
                  return reader.readLine();
              } catch (IOException e) {
                  throw new RuntimeException(e);
              }
          }
          return tokenizer.nextToken("\n");
      }
  
      public long nextLong() {
          return Long.parseLong(next());
      }
  
      public int nextInt() {
          return Integer.parseInt(next());
      }
  
      public double nextDouble() {
          return Double.parseDouble(next());
      }
  
      public String[] nextArray(int n) {
          String[] a = new String[n];
          for (int i = 0; i < n; i++)
              a[i] = next();
          return a;
      }
  
      public int[] nextIntArray(int n) {
          int[] a = new int[n];
          for (int i = 0; i < n; i++)
              a[i] = nextInt();
          return a;
      }
  
      public long[] nextLongArray(int n) {
          long[] a = new long[n];
          for (int i = 0; i < n; i++)
              a[i] = nextLong();
          return a;
      }
  }
  