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.*;
  import java.util.concurrent.TimeUnit;
  
  public class c1622 implements Runnable{
      
      public static void main(String[] args) {
          try{
              new Thread(null, new c1622(), "process", 1<<26).start();
          }
          catch(Exception e){
              System.out.println(e);
          }
      }
      public void run() {
          FastReader scan = new FastReader();
          PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
  //      try {
  //            out = new PrintWriter("file.out");
  //        } catch (FileNotFoundException e) {
  //            // TODO Auto-generated catch block
  //            e.printStackTrace();
  //        }
          Task solver = new Task();
          int t = scan.nextInt();
          //int t = 1;
          for(int i = 1; i <= t; i++) solver.solve(i, scan, out);
          out.close();
      }
  
      static class Task {
          static final int oo = Integer.MAX_VALUE;
          static final long OO = Long.MAX_VALUE;
  
          public void solve(int testNumber, FastReader sc, PrintWriter out) {
              int N = sc.nextInt();
              long K = sc.nextLong();
              
              long[] arr = sc.readLongArray(N);
              shuffle(arr);
              Arrays.sort(arr);
              
              long sum = 0;
              for(int i = 0; i < N; i++) {
                  sum += arr[i];
              }
              
  //            dbg(gain);
              
              long curGain = 0;
              long best = Long.MAX_VALUE;
              for(int i = N; i >= 1; i--) {
                  long newSum;
                  if(i != N) {
                      curGain += arr[i] - arr[0];
                  }
                  newSum = sum - curGain;
                  
                  // Calculate new value for arr[0] necessary
                  if(newSum <= K) {
                      best = Math.min(best, (N - i));
                      break;
                  }
                  
                  long diff = newSum - K;
                  long x = (long)(Math.ceil((double)(diff) / (N - i + 1)));
                  best = Math.min(best, N - i + x);
              }
              
              out.println(best);
          }
      }
      
      static long modDivide(long a, long b, long MOD) {
          a %= MOD;
          return (binpow(b, MOD-2, MOD) * a) % MOD;
      }
      static long binpow(long a, long b, long m) {
          a %= m;
          long res = 1;
          while (b > 0) {
              if ((b & 1) == 1)
                  res = res * a % m;
              a = a * a % m;
              b >>= 1;
          }
          return res;
      }
      static int[] reverse(int a[]) 
      { 
          int[] b = new int[a.length]; 
          for (int i = 0, j = a.length; i < a.length; i++, j--) { 
              b[j - 1] = a[i]; 
          } 
          
          return b;
      }
      static long[] reverse(long a[]) 
      { 
          long[] b = new long[a.length]; 
          for (int i = 0, j = a.length; i < a.length; i++, j--) { 
              b[j - 1] = a[i]; 
          } 
          
          return b;
      }
      static void sort(int[] x){
          shuffle(x);
          Arrays.sort(x);
      }
      static void sort(long[] x){
          shuffle(x);
          Arrays.sort(x);
      }
      static class tup implements Comparable<tup>, Comparator<tup>{
          int a, b;
          tup(int a,int b){
              this.a=a;
              this.b=b;
          }
          public tup() {
          }
          @Override
          public int compareTo(tup o){
              return Integer.compare(b,o.b);
          }
          @Override
          public int compare(tup o1, tup o2) {
              return Integer.compare(o1.b, o2.b);
          }
          
          @Override
          public int hashCode() {
              return Objects.hash(a, b);
          }
   
          @Override
          public boolean equals(Object obj) {
              if (this == obj)
                  return true;
              if (obj == null)
                  return false;
              if (getClass() != obj.getClass())
                  return false;
              tup other = (tup) obj;
              return a==other.a && b==other.b;
          }
          
          @Override
          public String toString() {
              return a + " " + b;
          }
      }
      
      static void shuffle(int[] a) {
          Random get = new Random();
          for (int i = 0; i < a.length; i++) {
              int r = get.nextInt(a.length);
              int temp = a[i];
              a[i] = a[r];
              a[r] = temp;
          }
      }
  
      static void shuffle(long[] a) {
          Random get = new Random();
          for (int i = 0; i < a.length; i++) {
              int r = get.nextInt(a.length);
              long temp = a[i];
              a[i] = a[r];
              a[r] = temp;
          }
      }
  
      static class FastReader {
          BufferedReader br;
          StringTokenizer st;
  
          public FastReader() {
              br = new BufferedReader(new InputStreamReader(System.in));
          }
  
          public FastReader(String s) throws FileNotFoundException {
              br = new BufferedReader(new FileReader(new File(s)));
          }
  
          String next() {
              while (st == null || !st.hasMoreElements()) {
                  try {
                      st = new StringTokenizer(br.readLine());
                  } catch (IOException e) {
                      e.printStackTrace();
                  }
              }
              return st.nextToken();
          }
  
          int nextInt() {
              return Integer.parseInt(next());
          }
  
          long nextLong() {
              return Long.parseLong(next());
          }
  
          double nextDouble() {
              return Double.parseDouble(next());
          }
  
          String nextLine() {
              String str = "";
              try {
                  str = br.readLine();
              } catch (IOException e) {
                  e.printStackTrace();
              }
              return str;
          }
          
          int[] readArray(int size) {
              int[] a = new int[size];
              for(int i = 0; i < size; i++) {
                  a[i] = nextInt();
              }
              return a;
          }
          
          long[] readLongArray(int size) {
              long[] a = new long[size];
              for(int i = 0; i < size; i++) {
                  a[i] = nextLong();
              }
              return a;
          }
      }
      
      static void dbg(int[] arr) {
          System.out.println(Arrays.toString(arr));
      }
      static void dbg(long[] arr) {
          System.out.println(Arrays.toString(arr));
      }
      static void dbg(boolean[] arr) {
          System.out.println(Arrays.toString(arr));
      }
  
      static void dbg(Object... args) {
          for (Object arg : args)
              System.out.print(arg + " ");
          System.out.println();
      }
  }