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.time.*;
  import static java.lang.Math.*;
  
  @SuppressWarnings("unused")
  public class C {
  	static boolean DEBUG = false;
  
  	static Reader fs;
  	static PrintWriter pw;
  
  	static void solve() {
  		int n = fs.nextInt();
  		long k = fs.nextLong();
  		int a[] = fs.readArray(n);
  		long ans = Long.MAX_VALUE;
  		sort(a);
  		long pre[] = new long[n + 1];
  		for (int i = 1; i < n + 1; i++)
  			pre[i] = pre[i - 1] + a[i - 1];
  		lg(pre);
  		long sum = pre[n];
  		for (int i = 1; i <= n; i++) {
  			int to_be_set = i - 1;
  			long sum_of_window = pre[n] - pre[n - to_be_set] - a[0] * (long) to_be_set;
  			long need = pre[n] - sum_of_window - k;
  			need = max(need, 0);
  			long moves = to_be_set + (need + to_be_set) / i;
  			ans = min(moves, ans);
  		}
  		pw.println(ans);
  	}
  
  	public static void main(String[] args) throws IOException {
  		Instant start = Instant.now();
  		if (args.length == 2) {
  			System.setIn(new FileInputStream(new File("D:\\program\\javaCPEclipse\\CodeForces\\src\\input.txt")));
  			// System.setOut(new PrintStream(new File("output.txt")));
  			System.setErr(new PrintStream(new File("D:\\program\\javaCPEclipse\\CodeForces\\src\\error.txt")));
  			DEBUG = true;
  		}
  		fs = new Reader();
  		pw = new PrintWriter(System.out);
  		int t = fs.nextInt();
  		while (t-- > 0) {
  			solve();
  		}
  		Instant end = Instant.now();
  		if (DEBUG) {
  			pw.println(Duration.between(start, end));
  		}
  		pw.close();
  	}
  
  	static void sort(int a[]) {
  		ArrayList<Integer> l = new ArrayList<Integer>();
  		for (int x : a)
  			l.add(x);
  		Collections.sort(l);
  		for (int i = 0; i < a.length; i++) {
  			a[i] = l.get(i);
  		}
  	}
  
  	static void lg(Object o) {
  		if (DEBUG)
  			System.err.println(o);
  	}
  
  	static void lg(int a[]) {
  		if (DEBUG)
  			System.err.println(Arrays.toString(a));
  	}
  
  	static void lg(char a[]) {
  		if (DEBUG)
  			System.err.println(Arrays.toString(a));
  	}
  
  	static void lg(long a[]) {
  		if (DEBUG)
  			System.err.println(Arrays.toString(a));
  	}
  
  	static void lg(String a) {
  		if (DEBUG)
  			System.err.print(a + " -> ");
  	}
  
  	static <T> void lg(T a[]) {
  		if (DEBUG) {
  			System.err.print("[");
  			for (T x : a)
  				System.err.print(x + " ");
  			System.err.println("]");
  		}
  	}
  
  	static <T> void lg(ArrayList<T> a) {
  		if (DEBUG) {
  			System.err.print("[");
  			for (T x : a) {
  				System.err.print(x + " ");
  			}
  			System.err.println("]");
  		}
  	}
  
  	static <T, V> void lg(Map<T, V> mp) {
  		if (DEBUG) {
  			System.err.print(mp);
  		}
  	}
  
  	public static void print(long a, long b, long c, PrintWriter pw) {
  		pw.println(a + " " + b + " " + c);
  		return;
  	}
  
  	static class Reader {
  		BufferedReader br;
  		StringTokenizer st;
  
  		public Reader() {
  			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;
  		}
  
  		int[] readArray(int n) {
  			int a[] = new int[n];
  			for (int i = 0; i < n; i++)
  				a[i] = nextInt();
  			return a;
  		}
  
  		int[][] read2Array(int n, int m) {
  			int a[][] = new int[n][m];
  			for (int i = 0; i < n; i++) {
  				for (int j = 0; j < m; j++) {
  					a[i][j] = nextInt();
  				}
  			}
  			return a;
  		}
  	}
  }