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: /*
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                        88" . "88
                        (| -_- |)
                        0\  =  /0
                      ___/`---'\___
                    .' \\|     |// '.
                   / \\|||  :  |||// \
                  / _||||| -:- |||||- \
                 |   | \\\  -  /// |   |
                 | \_|  ''\---/''  |_/ |
                 \  .-\__  '-'  ___/-. /
               ___'. .'  /--.--\  `. .'___
            ."" '<  `.___\_<|>_/___.' >' "".
           | | :  `- \`.;`\ _ /`;.`/ - ` : | |
           \  \ `_.   \_ __\ /__ _/   .-` /  /
       =====`-.____`.___ \_____/___.-`___.-'=====
                         `=---='
   
  */
  
  import java.util.*;
  import java.math.*;
  import java.io.*;
  import java.lang.Math.*;
  
  public class KickStart2020 {
  	 static class FastReader {
  		BufferedReader br;
  		StringTokenizer st;
  
  		public FastReader() {
  			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());
  		}
  
  		float nextFloat() {
  			return Float.parseFloat(next());
  		}
  
  		String nextLine() {
  			String str = "";
  			try {
  				str = br.readLine();
  			} catch (IOException e) {
  				e.printStackTrace();
  			}
  			return str;
  		}
  	}
  
  	static long gcd(long a, long b) {
  		if (b == 0)
  			return a;
  		return gcd(b, a % b);
  
  	}
  	static long lcm(long a, long b) {
  		return a / gcd(a, b) * b;
  	}
  
  	public static class Pair implements Comparable<Pair> {
  		public int index;
  		public int value;
  
  		public Pair(int index, int value) {
  			this.index = index;
  			this.value = value;
  		}
  
  		@Override
  		public int compareTo(Pair other) {
  			// multiplied to -1 as the author need descending sort order
  			if(other.index < this.index) return -1;
  			if(other.index > this.index) return 1;
  			return 0;
  		}
  		@Override
  		public String toString() {
  			return this.index + " " + value;
  		}
  	}
  	static boolean isPrime(long d) {
  		if (d == 3)
  			return false;
  		for (int i = 2; i <= (long) Math.sqrt(d); i++) {
  			if (d % i == 0)
  				return false;
  		}
  		return true;
  	}
  	static void decimalTob(int n, int k, int j, int arr[]) {
            int x = n % k;
            int y = n / k;
            arr[j++] += x;
            if(y > 0) {
          	   decimalTob(y, k, j, arr);
            }
  	}
  	static long powermod(long x, long y, long mod) {
  		long ans = 1;
  		x = x % mod;
  		if (x == 0)
  			return 0;
  		int i = 1;
  		while (y > 0) {
  			if ((y & 1) != 0)
  				ans = (ans * x) % mod;
  			y = y >> 1;
  			x = (x * x) % mod;
  		}
  		return ans;
  	}
  	static long power(long x, long y)
  	{
  	    long res = 1;
  	    while (y > 0)
  	    {
  	        if ((y & 1) != 0)
  	            res = res * x;	  
  	        y = y >> 1; 
  	        x = x * x;  
  	    }
  	    return res;}
  	static boolean check(long m, long arr[]) {
  		int n = arr.length;
  		long brr[] = new long[n];
  		for(int i = 0; i < n; i++) brr[i] = arr[i];
  		for(int i = n - 1; i >= 2; i--) {
  			long diff = Math.min(brr[i] - m, arr[i] - (arr[i] % 3));
  			if(diff < 0) return false;
  			diff /= 3;
  			brr[i] -= 3 * diff;
  			brr[i - 1] += diff;
  			brr[i - 2] += 2 * diff;
  		}
  		return brr[0] >= m && brr[1] >= m;
  	}
  	public static void main(String[] args) throws Exception {
  		FastReader sc = new FastReader();
  		PrintWriter out = new PrintWriter(System.out);
  		int t = sc.nextInt();
  		outerloop:
  			while(t-- > 0) {
            int n = sc.nextInt();
            long k = sc.nextLong();
            ArrayList<Long> ss = new ArrayList<>();
             for(int i = 0; i < n; i++) ss.add(sc.nextLong());
             Collections.sort(ss);
             long count[] = new long[n];
             count[0] = ss.get(0);
             for(int i = 1; i < n; i++) {
          	   count[i] = count[i - 1] + ss.get(i);
             }
             long ans = Integer.MAX_VALUE;
             for(int j = 0; j <= n - 1; j++) {
          	   long x = (long)ss.get(0) - (long)Math.floor((k - count[n - 1 - j] + (long)ss.get(0)) / ((j  + 1) * 1.0) );
          	   ans = Math.min(ans,Math.max(0l, x) + j);
             }
             out.println(ans);
  			}
  		out.close();
  	}
  }