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.*;
  import java.lang.*;
  import java.rmi.dgc.Lease;
  
  // Problem - Multiples of 3 onn codeforces MNedium difficulty level 
  // or check on youtube channel CodeNCode
  
  public class Problem {
       static int Mod = 1000000007;
      static long dp[][];
      static int g[][];
      static int fact[];
  
  
      public static void main(String[] args) {
          MyScanner scan = new MyScanner();
          PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
           int t = scan.nextInt();
          // int t = 1;
          while (t-- > 0) {
              int n= scan.nextInt();
              long k= scan.nextLong();
              long a[]= new long[n];
              long pre_sum=0;
              for(int i=0;i<n;i++ ){
                   a[i]= scan.nextLong();
                   pre_sum+=a[i];
              }
              sort(a);
              if(pre_sum<=k){
                  out.println(0);
                  continue;
              }
              if(pre_sum==k+1){
                  out.println(1);
                  continue;
              }
              pre_sum-=k;
              long sum=0;
              long ans= pre_sum;
              for(int i=n-1;i>=1;i--){
                    sum+=a[i];
                    long x;
                    if((sum-(n-i)*a[0])>=pre_sum) x=0l;
                    else {
                        x= Math.max((long)Math.ceil((double)(pre_sum-sum+(n-i)*a[0])/(double)(n-i+1)),0l);
                      //   out.println(i+" "+x+" "+(pre_sum));
                      //   break;
                    }
                    ans= Math.min(ans,x+n-i);
                     
              }
    
              out.println(ans);
  
          }
  
          out.close();
      }
  
   
  
  
  
      static ArrayList<Integer> digits(long n){
          ArrayList<Integer> list= new ArrayList<>();
          while(n>0){
              list.add((int)(n%10l));
              n=n/10l;
          }
          Collections.reverse(list);
          return list;
      }
  
      
      int upper_bound(long[] arr, int key) {
          int i=0, j=arr.length-1;
          if (arr[j]<=key) return j+1;
          if(arr[i]>key) return i;
          while (i<j){
              int mid= (i+j)/2;
              if(arr[mid]<=key){
                  i= mid+1;
              }else{
                  j=mid;
              }
          }
          return i;
      }
  
      static class Pair {
          int l;
          int r;
  
          Pair(int l, int r) {
              this.l = l;
              this.r = r;
          }
  
          @Override
          public int hashCode() {
              final int prime = 31;
              int result = 1;
              result = prime * result + l;
              result = prime * result + r;
              return result;
          }
  
          @Override
          public boolean equals(Object obj) {
              if (this == obj)
                  return true;
              if (obj == null)
                  return false;
              if (getClass() != obj.getClass())
                  return false;
              Pair other = (Pair) obj;
              if (l != other.l)
                  return false;
              if (r != other.r)
                  return false;
              return true;
          }
  
          @Override
          public String toString() {
              return "Pair [l=" + l + ", r=" + r + "]";
          }
  
      }
  
      public static void reverse(int a[]) {
          int n = a.length;
          for (int i = 0; i < n / 2; i++) {
              int temp = a[i];
              a[i] = a[n - i - 1];
              a[n - i - 1] = temp;
          }
      }
  
      public static void sort(int[] array) {
          ArrayList<Integer> copy = new ArrayList<>();
          for (Integer i : array)
              copy.add(i);
          Collections.sort(copy);
          for (int i = 0; i < array.length; i++)
              array[i] = copy.get(i);
      }
  
      public static void sort(long[] array) {
          ArrayList<Long> copy = new ArrayList<>();
          for (Long i : array)
              copy.add(i);
          Collections.sort(copy);
          for (int i = 0; i < array.length; i++)
              array[i] = copy.get(i);
      }
  
      public static long gcd(long a, long b) {
          if (b == 0)
              return a;
          return gcd(b, a % b); // gcd(a,b) = gcd(a-b,b) or gcd(a,b) = gcd(b,a%b) where a>b
      }
  
      public static int gcd(int a, int b) {
          if (b == 0)
              return a;
          return gcd(b, a % b); // gcd(a,b) = gcd(a-b,b) or gcd(a,b) = gcd(b,a%b) where a>b
      }
  
      public static long lcm(long a, long b) {
          return (a / gcd(a, b)) * b;
      }
  
      static long power(long x, long y) {
          long temp;
          if (y == 0) // a^b= (a^b/2)^2 if b is even
              return 1; // = (a*a^(b-1)) if b is odd
          temp = power(x, y / 2);
          if (y % 2 == 0)
              return temp * temp;
          else
              return x * temp * temp;
      }
  
      static long mod(long x) {
          return ((x % Mod + Mod) % Mod);
      }
  
      static long add(long a, long b) {
          return mod(mod(a) + mod(b));
      }
  
      static int mod(int x) {
          return ((x % Mod + Mod) % Mod);
      }
  
      static int add(int a, int b) {
          return mod(mod(a) + mod(b));
      }
  
      static int sub(int a, int b) {
          return mod(mod(a) - mod(b) + Mod);
      }
  
      static long mul(long a, long b) {
          return mod(mod(a) * mod(b));
      }
  
      static long pow(long x, long y, long p) {
          long res = 1; // Initialize result
          x = x % p; // Update x if it is more than or equal to p
  
          if (x == 0)
              return 0; // In case x is divisible by p;
  
          while (y > 0) {
              // If y is odd, multiply x with result
              if ((y & 1) != 0)
                  res = (res * x) % p;
  
              // y must be even now
              y = y >> 1; // y = y/2
              x = (x * x) % p;
          }
          return res;
      }
  
      static long modInverse(long a, long m) {
          // int g = gcd(a, m);
          // if (g != 1)
          // System.out.println("Inverse doesn't exist");
          // else {
          // // If a and m are relatively prime, then modulo
          // // inverse is a^(m-2) mode m
          // return power(a, m - 2, m);
          // }
          return pow(a, m - 2, m);
      }
  
  }
  
  class MyScanner {
      BufferedReader br;
      StringTokenizer st;
  
      public MyScanner() {
          br = new BufferedReader(new InputStreamReader(System.in));
      }
  
      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;
      }
  
  }
  