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: // HOPE
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  //----------------------------------------------------------------------------------------------------------------------
  ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  //----------------------------------------------------------------------------------------------------------------------
  ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  ///////                                                                                                       //////////
  ///////                                                                                                       //////////
  ///////            RRRRRRRRRRRRR     YY          YY         AA               NN          NN                   //////////
  ///////            RR         RR      YY        YY        AA  AA             NN NN       NN                   //////////
  ///////            RR        RR         YY     YY        AA    AA            NN  NN      NN                   //////////
  ///////            RRRRRRRRRR            YY   YY       AAAAAAAAAAAA          NN    NN    NN                   //////////
  ///////            RR RR                   YY         AAAAAAAAAAAAAA         NN      NN  NN                   //////////
  ///////            RR   RR                 YY        AA            AA        NN       NN NN                   //////////
  ///////            RR     RR               YY       AA              AA       NN          NN                   //////////
  ///////            RR       RR_____________________________________________________________________________   //////////
  ////////                                                                                                      //////////
  ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  //----------------------------------------------------------------------------------------------------------------------
  ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  //----------------------------------------------------------------------------------------------------------------------
  ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.*;
  import java.math.*;
  
  public class Codeforces1 {
      static PrintWriter out = new PrintWriter(System.out);
      static final int mod = 1_000_000_007;
  
      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());
          }
  
          int[] readIntArray(int n) {
              int[] a = new int[n];
              for (int i = 0; i < n; i++)
                  a[i] = nextInt();
              return a;
          }
  
          long[] readLongArray(int n) {
              long[] a = new long[n];
              for (int i = 0; i < n; i++)
                  a[i] = nextLong();
              return a;
          }
  
          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;
          }
      }
  
      //Try seeing general case
      public static void main(String[] args) {
          FastReader s = new FastReader();
          int t = s.nextInt();
          while(t-->0)
          {
              int n = s.nextInt();
              long k = s.nextLong();
              long[] a = s.readLongArray(n);
              sort(a);
              long[] pre = new long[n+1];
              for(int i=1;i<=n;i++)
              {
                  pre[i] = pre[i-1] + a[i-1];
              }
  
              out.println(find(n, k, a, pre));
          }
  
  
          out.close();
      }
  
      public static long find(int n, long k, long[] a, long[] pre)
      {
          if(pre[n]<=k)
              return 0;
  
          long res = Long.MAX_VALUE;
          for(int i=0;i<n;i++)
          {
              long sum = pre[n-i] + a[0]*i;
              long steps = i;//Elements on the right only changed once.
              if(sum>k)
                  steps += (long)Math.ceil((sum-k)/(i+1.0));
              //Check how many times we need to dec. a[0] and then replace numbers on right with that no.
              res = Math.min(res, steps);
          }
          return res;
      }
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
      /////////////////////////////////////////////////THE END///////////////////////////////////////////////////////////
      //////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  
      public static int gcd(int x,int y)
      {
          return y==0?x:gcd(y,x%y);
      }
      public static long gcd(long x,long y)
      {
          return y==0L?x:gcd(y,x%y);
      }
  
      public static int lcm(int a, int b) {
          return (a * b) / gcd(a, b);
      }
      public static long lcm(long a, long b) {
          return (a * b) / gcd(a, b);
      }
  
      public static long pow(long a,long b)
      {
          if(b==0L)
              return 1L;
          long tmp=1;
          while(b>1L)
          {
              if((b&1L)==1)
                  tmp*=a;
              a*=a;
              b>>=1;
          }
          return (tmp*a);
      }
  
      public static long modPow(long a,long b,long mod)
      {
          if(b==0L)
              return 1L;
          long tmp=1;
          while(b>1L)
          {
              if((b&1L)==1L)
                  tmp*=a;
  
              a*=a;
              a%=mod;
              tmp%=mod;
              b>>=1;
          }
          return (tmp*a)%mod;
      }
  
      static long mul(long a, long b) {
          return a*b%mod;
      }
  
      static long fact(int n) {
          long ans=1;
          for (int i=2; i<=n; i++) ans=mul(ans, i);
          return ans;
      }
  
      static long fastPow(long base, long exp) {
          if (exp==0) return 1;
          long half=fastPow(base, exp/2);
          if (exp%2==0) return mul(half, half);
          return mul(half, mul(half, base));
      }
  
      static void debug(int ...a)
      {
          for(int x: a)
              out.print(x+" ");
          out.println();
      }
  
      static void debug(long ...a)
      {
          for(long x: a)
              out.print(x+" ");
          out.println();
      }
  
      static void debugMatrix(int[][] a)
      {
          for(int[] x:a)
              out.println(Arrays.toString(x));
      }
      static void debugMatrix(long[][] a)
      {
          for(long[] x:a)
              out.println(Arrays.toString(x));
      }
  
      static void reverseArray(int[] a, int start, int end) {//[start end)
          while(start<end)
          {
              int temp = a[start];
              a[start] = a[end];
              a[end] = temp;
              start++; end--;
          }
      }
  
      static void reverseArray(long[] a, int start, int end) {
          while(start<end)
          {
              long temp = a[start];
              a[start] = a[end];
              a[end] = temp;
              start++; end--;
          }
      }
  
      static void sort(int[] a)
      {
          ArrayList<Integer> ls = new ArrayList<>();
          for(int x: a) ls.add(x);
          Collections.sort(ls);
          for(int i=0;i<a.length;i++)
              a[i] = ls.get(i);
      }
  
      static void sort(long[] a)
      {
          ArrayList<Long> ls = new ArrayList<>();
          for(long x: a) ls.add(x);
          Collections.sort(ls);
          for(int i=0;i<a.length;i++)
              a[i] = ls.get(i);
      }
  
      static class Pair{
          int x, y;
          Pair(int x, int y)
          {
              this.x = x;
              this.y = y;
          }
  
          @Override
          public String toString() {
              return "Pair{" +
                      "x=" + x +
                      ", y=" + y +
                      '}';
          }
      }
      static class MyCmp implements Comparator<Pair>
      {
          public int compare(Pair p1, Pair p2)
          {
              return p1.x-p2.x;
          }
      }
  }