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.io.OutputStream;
  import java.io.PrintWriter;
  import java.math.BigInteger;
  import java.util.*;
  
  /**
   * @author Mubtasim Shahriar
   */
  
  public class Ecr120 {
  
      public static void main(String[] args) {
  
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          InputReader sc = new InputReader(inputStream);
          PrintWriter out = new PrintWriter(outputStream);
          Solver solver = new Solver();
          int t = sc.nextInt();
  //        int t = 1;
          while (t-- != 0) {
              solver.solve(sc, out);
          }
          out.close();
  
      }
  
      static class Solver {
          final long stress = (long) 1e16;
          public void solve(InputReader sc, PrintWriter out) {
              int n = sc.nextInt();
              long k = sc.nextLong();
              long[] arr = sc.nextLongArray(n);
              long sum = 0;
              for(long l : arr) sum += l;
              if(sum<=k) {
                  out.println(0);
                  return;
              }
              long extra = sum - k;
              sort(arr);
              long ans = extra;
              long totalDiff = 0;
              for(int i = n-1; i > 0; i--) {
                  totalDiff += arr[i]-arr[0];
                  long takenLast = n-i;
                  if(totalDiff>=extra) {
                      ans = Math.min(ans,takenLast);
                      continue;
                  }
                  long rest = extra-totalDiff;
                  long l = 0;
                  long r = rest;
                  while(l<=r) {
                      long mid = (l+r)/2;
                      if(mid>=stress/takenLast) {
                          ans = Math.min(ans,takenLast+mid);
                          r = mid-1;
                          continue;
                      }
                      long newDiff = totalDiff;
                      newDiff += mid*takenLast;
                      newDiff += mid;
                      if(newDiff>=extra) {
                          ans = Math.min(ans,takenLast+mid);
                          r = mid-1;
                      } else {
                          l = mid+1;
                      }
                  }
              }
              out.println(ans);
          }
      }
  
      static void sort(int[] arr) {
          ArrayList<Integer> al = new ArrayList();
          for (int i : arr) al.add(i);
          Collections.sort(al);
          int idx = 0;
          for (int i : al) arr[idx++] = i;
      }
  
      static void sort(long[] arr) {
          ArrayList<Long> al = new ArrayList();
          for (long i : arr) al.add(i);
          Collections.sort(al);
          int idx = 0;
          for (long i : al) arr[idx++] = i;
      }
  
      static void sortDec(int[] arr) {
          ArrayList<Integer> al = new ArrayList();
          for (int i : arr) al.add(i);
          Collections.sort(al, Collections.reverseOrder());
          int idx = 0;
          for (int i : al) arr[idx++] = i;
      }
  
      static void sortDec(long[] arr) {
          ArrayList<Long> al = new ArrayList();
          for (long i : arr) al.add(i);
          Collections.sort(al, Collections.reverseOrder());
          int idx = 0;
          for (long i : al) arr[idx++] = i;
      }
  
      static 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 {
              public 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;
          }
      }
  
  
  }
  