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){
  		FastReader sc = new FastReader();
  		int t=sc.nextInt();
  		while(t-->0){
  			int n=sc.nextInt();
  			long k=sc.nextLong();
  			int a[]=sc.fastArray(n);
  			sort(a);
  			long sum=0;
  			long ans=Long.MAX_VALUE;
  			for(int i=1;i<n;i++)sum+=a[i];int j=0;
  			for(int i=n-1;i>=0;i--,j++) {
  				long rem_val=k-sum;
  				long val=find_div(rem_val,(j+1));
  				ans=Math.min(ans, j+Math.max(0l, a[0]-val));
  				sum-=a[i];
  			}
  			System.out.println(ans);
  			
  			
  		}		 
      }
  	static  long find_div(long x,long y) {
  		if(x>=0)return x/y;
  		else return (x-y+1)/y;
  	}
  	static class pair {
  		int x;int y;
  		 pair(int x,int y){
  			this.x=x;
  			this.y=y;
  		}
  		
  	}
  	static void sort(int a[]) {
  		ArrayList<Integer> aa= new ArrayList<>();
  		for(int i:a)aa.add(i);
  		Collections.sort(aa);
  		int j=0;
  		for(int i:aa)a[j++]=i;
  	}
  	static ArrayList<Integer> primeFac(int n){
  		ArrayList<Integer>ans = new ArrayList<Integer>();
  		int lp[]=new int [n+1];
  		Arrays.fill(lp, 0);  	//0-prime
  		for(int i=2;i<=n;i++) {
  			if(lp[i]==0) {
  				for(int j=i;j<=n;j+=i) {
  					if(lp[j]==0) lp[j]=i;
  				}
  			}
  		}
  		int fac=n;
  		while(fac>1) {
  			ans.add(lp[fac]);
  			fac=fac/lp[fac];
  		}
  		print(ans);
  		return ans;
  	}
  	static ArrayList<Long> prime_in_given_range(long l,long r){
  		ArrayList<Long> ans= new ArrayList<>();
  		int n=(int)Math.sqrt(r)+1;
  		int prime[]=sieve_of_Eratosthenes(n);
  		long res[]=new long [(int)(r-l)+1];
  		for(int i=0;i<=r-l;i++) {
  			res[i]=i+l;
  		}
  		for(int i=0;i<prime.length;i++) {
  			if(prime[i]==1) {
  				System.out.println(2);
  				for(int j=Math.max((int)i*i, (int)(l+i-1)/i*i);j<=r;j+=i) {
  					res[j-(int)l]=0; 
  				}
  			}
  		}
  		for(long i:res) if(i!=0)ans.add(i);
  		return ans;
  	}
  	static int [] sieve_of_Eratosthenes(int n) {
  		int prime[]=new int [n];
  		Arrays.fill(prime, 1);  // 1-prime | 0-not prime
  		prime[0]=prime[1]=0;
  		for(int i=2;i<n;i++) {
  			if(prime[i]==1) {
  				for(int j=i*i;j<n;j+=i) {
  					prime[j]=0;
  				}
  			}
  		}
  		return prime;
  	}
  	static long binpow(long a,long b) {
  		long res=1;
  		if(b==0)return a;
  		if(a==0)return 1;
  		while(b>0) {
  			if((b&1)==1) {
  				res*=a;
  			}
  			a*=a;
  			b>>=1;
  		}
  		return res;
  	}
  	static void print(int a[]) {
  		System.out.println(a.length);
  		for(int i:a) {
  			System.out.print(i+" ");
  		}
  		System.out.println();
  	}
  	static void print(long a[]) {
  		System.out.println(a.length);
  		for(long i:a) {
  			System.out.print(i+" ");
  		}
  		System.out.println();
  	}
  	static void print(ArrayList<Integer> a) {
  		System.out.println(a.size());
  		for(long i:a) {
  			System.out.print(i+" ");
  		}
  		System.out.println();
  	}
  	static class FastReader {
  		BufferedReader br;
  		StringTokenizer st;
  
  		public FastReader()
  		{
  			br = new BufferedReader(
  				new InputStreamReader(System.in));
  		}
  		int [] fastArray(int n) {
  			int a[]=new int [n];
  			for(int i=0;i<n;i++) {
  				a[i]=nextInt();
  			}
  			return a;
  		}
  		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;
  		}
  	}
  
  }