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: /*
   * Everything is Hard 
   * Before Easy 
   * Jai Mata Dii 
   */ 
   
  import java.util.*;
  import java.io.*; 
    
  public class Main {
  	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());}String nextLine(){String str = ""; try{str = br.readLine(); } catch (IOException e) {e.printStackTrace();} return str; }} 
  	static long mod = (long)(1e9+7); 
  //	 static long mod = 998244353; 
  //	 static Scanner sc = new Scanner(System.in); 
  	static FastReader sc = new FastReader(); 
  	static PrintWriter out = new PrintWriter(System.out);
  	static int ans;
  	public static void main (String[] args) {
  		int ttt = 1;
  		ttt = sc.nextInt();
  		z :for(int tc=1;tc<=ttt;tc++){
  			int n = sc.nextInt();
  			long k = sc.nextLong();
  			
  			long a[] = new long[n];
  			long sum = 0;
  			
  			for(int i=0;i<n;i++) {
  				a[i] = sc.nextLong();
  				sum = sum + a[i];
  			}
  			
  			if(sum<=k) {
  				out.write("0\n");
  				continue;
  			}
  			
  			sort(a);
  			
  			for(long val : a) {
  //				out.write(val+" ");
  			}
  //			out.write("\n");
  			
  			long steps = sum-k;
  			long csum = 0;
  			
  //			for(int i=0;i<n;i++) {
  //				if(a[0]*(1L*(n-i))+csum<=k) {
  //					steps = Math.min(steps, n-i);
  //				}
  //				else if(csum-a[0]<=k){
  //					long nsum = csum - a[0];
  //					if(i == 0) nsum += a[0];
  //					long div = (k-nsum)/(1L*(n-i));
  //					long cSteps = (a[0] - div) + (n - i);
  //					steps = Math.min(steps, cSteps);
  //				}
  //				csum = csum + a[i];
  //			}
  			
  			sum -= a[0];
  			
  			for(int i=n-1;i>=0;i--) {
  				if(i == 0) {
  					if(sum + a[0]*(n-i)<=k) {
  						steps = Math.min(steps, n-i);
  						continue;
  					}
  					long cnt = n-i;
  					long div = (k - 0)/cnt;
  //					if(sum+div*cnt>k) div--;
  //					if(sum+(div+1)*cnt<=k) div++;
  					steps = Math.min(steps, a[0]-div+n-i-1);
  					continue;
  				}
  				sum -= a[i];
  				if(sum + a[0]*(n-i+1)<=k) {
  					steps = Math.min(steps, n-i);
  				}
  				long cnt = n-i+1;
  				long div = (k - sum)/cnt;
  				if(sum+div*cnt>k) div--;
  				if(sum+(div+1)*cnt<=k) div++;
  				if(div<=a[0]) {
  					steps = Math.min(steps, a[0]-div+n-i);
  				}
  //				if(i == 6) System.out.println(sum+" "+cnt+" "+div);
  			}
  			out.write(steps+"\n");
  		}
  		out.close();
  	}
  
  	static long pow(long a, long b){long ret = 1;while(b>0){if(b%2 == 0){a = (a*a)%mod;b /= 2;}else{ret = (ret*a)%mod;b--;}}return ret%mod;}
  	static long gcd(long a,long b){if(b==0) return  a; return gcd(b,a%b); } 
  	private static void sort(int[] a) {List<Integer> k = new ArrayList<>();for(int val : a) k.add(val);Collections.sort(k);for(int i=0;i<a.length;i++) a[i] = k.get(i);} 
  	private static void ini(List<Integer>[] tre2){for(int i=0;i<tre2.length;i++){tre2[i] = new ArrayList<>();}} 
  	private static void init(List<int[]>[] tre2){for(int i=0;i<tre2.length;i++){tre2[i] = new ArrayList<>();}} 
  	private static void sort(long[] a) {List<Long> k = new ArrayList<>();for(long val : a) k.add(val);Collections.sort(k);for(int i=0;i<a.length;i++) a[i] = k.get(i);} 
  }