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 static java.lang.Math.*;
  import java.io.*;
  public class S {
         
      public static int surv = 0;
      
      public static void main(String args[])throws IOException{
          BufferedReader br = new  BufferedReader(new InputStreamReader(System.in));
          int test = Integer.parseInt(br.readLine());
          StringBuilder sb = new StringBuilder();
          while(test > 0){
              test--;
              StringTokenizer st = new StringTokenizer(br.readLine());
              int n = Integer.parseInt(st.nextToken());
              long k = Long.parseLong(st.nextToken());
              int a[] = new int[n];
              st = new StringTokenizer(br.readLine());
              for(int i = 0; i < n; i++){
                  a[i] = Integer.parseInt(st.nextToken());
              }
              solve(a, n, k, sb);
          }
          System.out.print(sb.toString());
      }
      
      final static int MOD = 1000000007;
      
      public static void solve(int a[], int n, long k, StringBuilder sb){
          sort(a);
          long sum[] = new long[n];
          long p = 0;
          for(int i = 0; i < n; i++){
              p += a[i];
              sum[i] = p;
          }
          if(p <= k){
              sb.append(0+"\n");
              return;
          }
          long ans = Long.MAX_VALUE;
          for(int y = 0; y < n; y++){
              long z = k + (long)a[0] - sum[n-y-1];
              long x = (long)a[0] - accurateFloor(z, (long)(y+1));//z/(long)(y+1);
              ans = Math.min(ans, Math.max(0l, x) + y);
          }
          sb.append(ans + "\n");
      }
      
      
      public static long accurateFloor(long a, long b) {
      	long val = a / b;
      	while (val * b > a)
      		val--;
      	return val;
      }
      
      public static long powerr(long base, long exp){
          if(exp < 2)return base;
          if(exp % 2 == 0){
              long ans = powerr(base, exp/2) % MOD;
              ans *= ans;
              ans %= MOD;
              return ans;
          }else{
              return (((powerr(base, exp-1)) % MOD) * base) % MOD;
          }
      } 
      
      public static long power(long a, long b){
          if(b == 0)return 1l;
          long ans = power(a, b/2);
          ans *= ans;
          ans %= MOD;
          if(b % 2 != 0){
              ans *= a;
          }
          return ans % MOD;
      }
      
      public static int logLong(long a){
          int ans = 0;
          long b = 1;
          while(b < a){
              b*=2;
              ans++;
          }
          return ans;
      }
      
      public static void rec(int a[], int l, int r, int d, int d_map[]){
          if(l > r)return;
          if(l == r){
              d_map[a[l]] = d;
              return;
          }
          int max = 0;
          int max_ind = -1;
          for(int i = l; i <= r; i++){
              if(a[i] > max){
                  max_ind = i;
                  max = a[i];
              }
          }
          d_map[a[max_ind]] = d;
          rec(a, l, max_ind - 1, d+1, d_map);
          rec(a, max_ind + 1, r, d+1, d_map);
      }
      
      public static void sort(int a[]){
          List<Integer> l = new ArrayList<Integer>();
          for(int val : a){
              l.add(val);
          }
          Collections.sort(l);
          int k = 0;
          for(int val : l){
              a[k++] = val;
          }
      }
      
      public static void sortLong(long a[]){
          List<Long> l = new ArrayList<Long>();
          for(long val : a){
              l.add(val);
          }
          Collections.sort(l);
          int k = 0;
          for(long val : l){
              a[k++] = val;
          }
      }
      
      public static boolean isPal(String s){
          int l = 0;
          int r = s.length() - 1;
          while(l <= r){
              if(s.charAt(l) != s.charAt(r)){
                  return false;
              }
              l++;
              r--;
          }
          return true;
      }
      public static int gcd(int a, int b){
          if(b > a){
              int temp = a;
              a = b;
              b = temp;
          }
          if(b == 0)return a;
          return gcd(b, a%b);
      }
     /* public static long gcd(long a, long b){
          if(b > a){
              long temp = a;
              a = b;
              b = temp;
          }
          if(b == 0)return a;
          return gcd(b, a%b);
      }*/
     // public static long lcm(long a, long b){
       //   return a * b/gcd(a, b);
     // }
     
     /*public static class DJSet{
          public int a[];
          
          public DJSet(int n){
              this.a = new int[n];
              Arrays.fill(a, -1);
          }
          
          public int find(int val){
              if(a[val] >= 0){
                  a[val] = find(a[val]);
                  return a[val];
              }else{
                  return val;
              }
          }
          
          public boolean union(int val1, int val2){
              int p1 = find(val1);
              int p2 = find(val2);
              if(p1 == p2){
                  return false;
              }
              int size1 = Math.abs(a[p1]);
              int size2 = Math.abs(a[p2]);
              if(size1 >= size2){
                  a[p2] = p1;
                  a[p1] = (size1 + size2) * -1;
              }else{
                  a[p1] = p2;
                  a[p2] = (size1 + size2) * -1;
              }
              return true;
          }*/
      /*
      public static class DSU{
          public int a[];
          public DSU(int size){
              this.a = new int[size];
              Arrays.fill(a, -1);
          }
          
          public int find(int u){
              if(a[u] < 0)return u;
              a[u] = find(a[u]);
              return a[u];
          }
          
          public boolean union(int u, int v){
              int p1 = find(u);
              int p2 = find(v);
              if(p1 == p2)return false;
              int size1 = a[p1] * -1;
              int size2 = a[p2] * -1;
              if(size1 >= size2){
                  a[p2] = p1;
                  a[p1] = (size1 + size2) * -1;
              }else{
                  a[p1] = p2;
                  a[p2] = (size1 + size2) * -1;
              }
              return true;
          }
      }*/
  }