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.*;
  
  public class q3 {
      public static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  //    public static long mod = 1000000007;
  
      public static long evaluate(long[] arr,long fval,long k){
          long sum = fval;
          for(int i = 1;i < arr.length;i++) sum += arr[i];
  
          long ans = 0;
          for(int i = arr.length - 1;i > 0 && sum > k;i--){
              if(arr[i] > fval){
                  sum -= (arr[i] - fval);
                  ans++;
              }
          }
          if(sum > k)ans += sum - k;
          return ans;
      }
      public static void solve() throws Exception {
          String[] parts = br.readLine().split(" ");
          int n = Integer.parseInt(parts[0]);
          long k = Long.parseLong(parts[1]);
  
          long[] arr = new long[n];
  
          long sum = 0;
          parts = br.readLine().split(" ");
          for(int i = 0;i < n;i++){
              arr[i] = Integer.parseInt(parts[i]);
              sum += arr[i];
          }
  
          if(sum <= k){
              System.out.println(0);
              return;
          }
  
          sort(arr);
          if(n == 1){
              System.out.println(sum - k);
              return;
          }
  
          HashMap<Long,Integer> map = new HashMap<>();
          long ans = sum - k;
          long rs = 0;
  
          sum -= arr[0];
          for(int i = n - 1;i > 0;i--){
              map.put(arr[i],map.getOrDefault(arr[i],0) + 1);
              rs++;
              sum -= arr[i];
  
  //            if(sum > k) continue;
              long val = 0;
              if(sum <= k) val = (k - sum) / (rs + 1);
              else{
                  val = (k - sum) / (rs + 1);
                  if((k - sum) % (rs + 1) != 0) val--;
              }
  
              long cans = rs - map.getOrDefault(val,0);
              if(val < arr[0]) cans += arr[0] - val;
  
              ans = Math.min(ans,cans);
          }
          System.out.println(ans);
  
  
      }
  
      public static void main(String[] args) throws Exception {
          int tests = Integer.parseInt(br.readLine());
          for (int test = 1; test <= tests; test++) {
              solve();
          }
      }
  
  //    public static ArrayList<Integer> primes;
  //    public static void seive(int n){
  //        primes = new ArrayList<>();
  //        boolean[] arr = new boolean[n + 1];
  //        Arrays.fill(arr,true);
  //
  //        for(int i = 2;i * i <= n;i++){
  //            if(arr[i]) {
  //                for (int j = i * i; j <= n; j += i) {
  //                    arr[j] = false;
  //                }
  //            }
  //        }
  //        for(int i = 2;i <= n;i++) if(arr[i]) primes.add(i);
  //    }
  
  
  //    public static void sort(int[] arr){
  //        ArrayList<Integer> temp = new ArrayList<>();
  //        for(int val : arr) temp.add(val);
  //
  //        Collections.sort(temp);
  //
  //        for(int i = 0;i < arr.length;i++) arr[i] = temp.get(i);
  //    }
  
      public static void sort(long[] arr){
          ArrayList<Long> temp = new ArrayList<>();
          for(long val : arr) temp.add(val);
  
          Collections.sort(temp);
  
          for(int i = 0;i < arr.length;i++) arr[i] = temp.get(i);
      }
  //
  //    public static long power(long a,long b,long mod){
  //        if(b == 0) return 1;
  //
  //        long p = power(a,b / 2,mod);
  //        p = (p * p) % mod;
  //
  //        if(b % 2 == 1) return (p * a) % mod;
  //        return p;
  //    }
  //    public static long modDivide(long a,long b,long mod){
  //        return ((a % mod) * (power(b,mod - 2,mod) % mod)) % mod;
  //    }
  //
  //    public static int GCD(int a,int b){
  //        return b == 0 ? a : GCD(b,a % b);
  //    }
  //    public static long GCD(long a,long b){
  //        return b == 0 ? a : GCD(b,a % b);
  //    }
  //
  //    public static int LCM(int a,int b){
  //        return a * b / GCD(a,b);
  //    }
  //    public static long LCM(long a,long b){
  //        return a * b / GCD(a,b);
  //    }
  }
  