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.IOException;
  import java.io.InputStream;
  import java.math.BigInteger;
  import java.util.Arrays;
  import java.util.InputMismatchException;
  import java.util.PriorityQueue;
  
  public class Main {
  
      public static void main(String[] args) {
          // write your code here
          boolean readFromLocal = true;
          //readFromLocal = false;
          String filepath = "src/input.txt";
          //FileInputStream fileInputStream = new FileInputStream(filepath);
          InputReader inputReader = new InputReader(System.in);
          Solve s = new Solve();
          s.solve(inputReader);
      }
  }
  
  class Solve {
  
      public void solve(InputReader inputReader) {
          int t = inputReader.nextInt();
          long mod = 1000_000_000 + 9;
          PriorityQueue<Integer> priorityQueue = new PriorityQueue<>();
          long[] prefixSum = new long[2_00_000];
          while (t > 0) {
              t--;
              int n = inputReader.nextInt();
              long maxSum = inputReader.nextLong();
              for (int i = 0; i < n; i++) {
                  priorityQueue.offer(inputReader.nextInt());
              }
              prefixSum[0] = priorityQueue.poll();
              for (int i = 1; i < n; i++) {
                  prefixSum[i] = prefixSum[i-1] + priorityQueue.poll();
              }
              long maxSteps = Math.max(prefixSum[n-1]-maxSum,0);
              for (int y = 0; y < n ; y++) {
                  Double reductionNeeded = Double.valueOf((y)*prefixSum[0] + prefixSum[n-y-1]-maxSum);
                  long x = 0;
                  if (reductionNeeded > 0){
                      x = (long)Math.ceil(reductionNeeded/(y+1));
                  }
                  maxSteps = Math.min(maxSteps,x+y);
              }
              System.out.println(maxSteps);
          }
      }
  }
  
  class Pair implements Comparable<Pair> {
      int first,second;
  
      public Pair(int first, int second) {
          this.first = first;
          this.second = second;
      }
  
      @Override
      public int compareTo(Pair o) {
          return this.second - o.second;
      }
  }
  class Utils {
      static void swap(int[] res, int i, int j) {
          int temp = res[i];
          res[i] = res[j];
          res[j] = temp;
      }
  
      static long pow(long num, int n, long mod) {
          long res = num%mod;
          while (n > 0) {
              if ((n & 1) != 0) {
                  res = (res * num) % mod;
              }
              num = (num * num) % mod;
              n >>= 1;
          }
          return res;
      }
  
  }
  
  class InputReader {
      private boolean finished = false;
  
      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 peek() {
          if (numChars == -1) {
              return -1;
          }
          if (curChar >= numChars) {
              curChar = 0;
              try {
                  numChars = stream.read(buf);
              } catch (IOException e) {
                  return -1;
              }
              if (numChars <= 0) {
                  return -1;
              }
          }
          return buf[curChar];
      }
  
      public int nextInt() {
          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 long nextLong() {
          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 String nextString() {
          int c = read();
          while (isSpaceChar(c)) {
              c = read();
          }
          StringBuilder res = new StringBuilder();
          do {
              if (Character.isValidCodePoint(c)) {
                  res.appendCodePoint(c);
              }
              c = read();
          } while (!isSpaceChar(c));
          return res.toString();
      }
  
      public boolean isSpaceChar(int c) {
          if (filter != null) {
              return filter.isSpaceChar(c);
          }
          return isWhitespace(c);
      }
  
      public static boolean isWhitespace(int c) {
          return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
      }
  
      private String readLine0() {
          StringBuilder buf = new StringBuilder();
          int c = read();
          while (c != '\n' && c != -1) {
              if (c != '\r') {
                  buf.appendCodePoint(c);
              }
              c = read();
          }
          return buf.toString();
      }
  
      public String readLine() {
          String s = readLine0();
          while (s.trim().length() == 0) {
              s = readLine0();
          }
          return s;
      }
  
      public String readLine(boolean ignoreEmptyLines) {
          if (ignoreEmptyLines) {
              return readLine();
          } else {
              return readLine0();
          }
      }
  
      public BigInteger readBigInteger() {
          try {
              return new BigInteger(nextString());
          } catch (NumberFormatException e) {
              throw new InputMismatchException();
          }
      }
  
      public char nextCharacter() {
          int c = read();
          while (isSpaceChar(c)) {
              c = read();
          }
          return (char) c;
      }
  
      public double nextDouble() {
          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, nextInt());
              }
              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, nextInt());
                  }
                  if (c < '0' || c > '9') {
                      throw new InputMismatchException();
                  }
                  m /= 10;
                  res += (c - '0') * m;
                  c = read();
              }
          }
          return res * sgn;
      }
  
      public boolean isExhausted() {
          int value;
          while (isSpaceChar(value = peek()) && value != -1) {
              read();
          }
          return value == -1;
      }
  
      public String next() {
          return nextString();
      }
  
      public SpaceCharFilter getFilter() {
          return filter;
      }
  
      public void setFilter(SpaceCharFilter filter) {
          this.filter = filter;
      }
  
      public interface SpaceCharFilter {
          boolean isSpaceChar(int ch);
      }
  
      public int[] nextIntArray(int n) {
          int[] array = new int[n];
          for (int i = 0; i < n; ++i) array[i] = nextInt();
          return array;
      }
  
      public int[] nextSortedIntArray(int n) {
          int[] array = nextIntArray(n);
          Arrays.sort(array);
          return array;
      }
  
      public int[] nextSumIntArray(int n) {
          int[] array = new int[n];
          array[0] = nextInt();
          for (int i = 1; i < n; ++i) array[i] = array[i - 1] + nextInt();
          return array;
      }
  
      public long[] nextLongArray(int n) {
          long[] array = new long[n];
          for (int i = 0; i < n; ++i) array[i] = nextLong();
          return array;
      }
  
      public long[] nextSumLongArray(int n) {
          long[] array = new long[n];
          array[0] = nextInt();
          for (int i = 1; i < n; ++i) array[i] = array[i - 1] + nextInt();
          return array;
      }
  
      public long[] nextSortedLongArray(int n) {
          long[] array = nextLongArray(n);
          Arrays.sort(array);
          return array;
      }
  }