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.lang.*;
  import java.util.function.Supplier;
  
  import static java.lang.Math.*;
  
  // Sachin_2961 submission //
  public class Codeforces {
  
      static void solve() {
  
          int n = fs.nInt();
          long k = fs.nLong();
          int[]ar = new int[n];
          for(int i=0;i<n;i++) {
              ar[i] = fs.nInt();
          }
          if(n == 1){
              long diff = max(ar[0]-k,0);
              out.println(diff);
              return;
          }
          sort(ar);
          long ans = Long.MAX_VALUE;
          long[]pre = new long[n];
          for(int i=1;i<n;i++){
              pre[i] = pre[i-1]+ar[i];
          }
          for(int i=n-1;i>=0;i--){
              long sum = pre[i];
              long cnt = n - i;
              long req = k - sum;
              req = req/cnt;
              for(long x = req-5;x<=req+5;x++){
                  if( sum + cnt*x > k )continue;
                  long moves = 0;
                  if( x <= ar[0] )
                      moves += ar[0]-x;
                  moves += cnt-1;
                  ans = min(ans,moves);
              }
          }
          out.println(ans);
      }
  
      static class PairI{
          int f,s,w;
          PairI(int f,int s,int w){
              this.f = f;
              this.s = s;
              this.w = w;
          }
  
      }
      static class Pair{
          int f,s;
          Pair(int f,int s) {
              this.f = f;
              this.s = s;
          }
      }
      static boolean multipleTestCase = true;static FastScanner fs;static PrintWriter out;
      public static void main(String[]args){
          try{
              out = new PrintWriter(System.out);
              fs = new FastScanner();
              int tc = multipleTestCase?fs.nInt():1;
              while (tc-->0)solve();
              out.flush();
              out.close();
          }catch (Exception e){
              e.printStackTrace();
          }
      }
      static class FastScanner extends PrintWriter {
          private InputStream stream;
          private byte[] buf = new byte[1<<16];
          private int curChar, numChars;
          public FastScanner() { this(System.in,System.out); }
          public FastScanner(InputStream i, OutputStream o) {
              super(o);
              stream = i;
          }
          // file input
          public FastScanner(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 nInt() { // 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 nLong(){return Long.parseLong(next());}
          public double nextDouble() { return Double.parseDouble(next()); }
      }
      public static void sort(int[] arr){
          ArrayList<Integer> ls = new ArrayList<>();
          for(int x: arr)
              ls.add(x);
          Collections.sort(ls);
          for(int i=0; i < arr.length; i++)
              arr[i] = ls.get(i);
      }
      public static void sort(long[] arr){
          ArrayList<Long> ls = new ArrayList<>();
          for(long x: arr)
              ls.add(x);
          Collections.sort(ls);
          for(int i=0; i < arr.length; i++)
              arr[i] = ls.get(i);
      }
  }