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: # cook your dish here
  import sys
  import bisect
  from bisect import bisect_left as lb
  from bisect import bisect_right as rb
  input_=lambda: sys.stdin.readline().strip("\r\n")
  from math import log
  from math import gcd
  from math import atan2,acos
  from random import randint
  sa=lambda :input_()
  sb=lambda:int(input_())
  sc=lambda:input_().split()
  sd=lambda:list(map(int,input_().split()))
  sflo=lambda:list(map(float,input_().split()))
  se=lambda:float(input_())
  sf=lambda:list(input_())
  flsh=lambda: sys.stdout.flush()
  sys.setrecursionlimit(3*10**5)
  mod=10**9+7
  mod1=998244353
  gp=[]
  cost=[]
  dp=[]
  mx=[]
  ans1=[]
  ans2=[]
  special=[]
  specnode=[]
  a=0
  kthpar=[]
  def dfs2(root,par):
      if par!=-1:
          dp[root]=dp[par]+1
      for i in range(1,20):
          if kthpar[root][i-1]!=-1:
              kthpar[root][i]=kthpar[kthpar[root][i-1]][i-1]
      for child in gp[root]:
          if child==par:continue
          kthpar[child][0]=root
          dfs(child,root)
          
  ans=0
  a=[]
  n,k=0,0
  b=[]
  vis=[]
  tot=0
  time=[]
  time1=[]
  adj=[]
  mx=-1
  eps=0.0000001
  def hnbhai(tc):
      n,k=sd()
      a=sd()
      a.sort()
      if sum(a)<=k:
          print(0)
          return
      s=sum(a)
      tot=s-k
      right=0
      for i in range(n-1,0,-1):
          left=n-i
          right+=a[i]
          tot=min(tot,max(0,(s-right+a[0]*left-k+left)//(left+1))+left)
      print(tot)
      return
  for _ in range(sb()):
      hnbhai(_+1)
  