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.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.*;
   
  public class C {
   
  	public static void main(String[] args) {
  		FastScanner fs=new FastScanner();
  		int t=fs.nextInt();
  		while(t-->0) 
  		{
  			int n;
  			long k,sum=0L,temp=0L,min=Integer.MAX_VALUE;
  			n=fs.nextInt();
  			k=fs.nextLong();
  			int[] arr=fs.readArray(n);
  		    for(int i=0;i<n;i++)
  		        sum+=arr[i];
  		    sort(arr);
  		    Stack<Integer> s=new Stack<>();
  		    for(int i=1;i<n;i++){
  		        s.push(arr[i]-arr[0]);
  		    }
  		    while(!s.empty() && sum>k){
  		        min=Math.min(min,temp+(sum-k+temp)/(temp+1));
  		        sum-=s.peek();
  		        s.pop();
  		        temp++;
  		    }
  		    if(sum>k){
  		    	temp+=(sum-k+temp)/(temp+1);
  		    }
  		    System.out.println(Math.min(min, temp));
  		}
  	}
  	public static void kThLexString(String st,int k, int n)
  	{
  	// Set to store the unique substring
  	Set<String> z = new HashSet<String>();
  	
  	for(int i = 0; i < n; i++)
  	{
  	// String to create each substring
  	String pp = "";
  	
  	for(int j = i; j < i + k; j++)
  	{
  	if (j >= n)
  	break;
  	pp += st.charAt(j);
  	
  	// Adding to set
  	z.add(pp);
  	}
  	}
  	
  	// Converting set into a list
  	Vector<String> fin = new Vector<String>();
  	fin.addAll(z);
  	
  	// Sorting the strings int the list
  	// into lexicographical order
  	Collections.sort(fin);
  	
  	// Printing kth substring
  	System.out.print(fin.get(k - 1));
  	}
  	static long gcd(long a, long b)
      {
        if (b == 0)
          return a;
        return gcd(b, a % b);
      }
   
  	static void sort(int[] a) {
  		ArrayList<Integer> l=new ArrayList<>();
  		for (int i:a) l.add(i);
  		Collections.sort(l);
  		for (int i=0; i<a.length; i++) a[i]=l.get(i);
  	}
  	void shuffleArray(long[] arr){
          int n = arr.length;
          Random rnd = new Random();
          for(int i=0; i<n; ++i){
              long tmp = arr[i];
              int randomPos = i + rnd.nextInt(n-i);
              arr[i] = arr[randomPos];
              arr[randomPos] = tmp;
          }   
  }
  	
  	static class FastScanner {
  		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
  		StringTokenizer st=new StringTokenizer("");
  		String next() {
  			while (!st.hasMoreTokens())
  				try {
  					st=new StringTokenizer(br.readLine());
  				} catch (IOException e) {
  					e.printStackTrace();
  				}
  			return st.nextToken();
  		}
  		
  		int nextInt() {
  			return Integer.parseInt(next());
  		}
  		int[] readArray(int n) {
  			int[] a=new int[n];
  			for (int i=0; i<n; i++) a[i]=nextInt();
  			return a;
  		}
  		long nextLong() {
  			return Long.parseLong(next());
  		}
  	}
   
  	
  }