#include<bits/stdc++.h>
#define ll long long
using namespace std;

int main(){
  int t;
  cin >> t;
  while (t--){
    int n, k, ans = 0;
    cin >> n >> k;
    map<int, int> mp;
    vector<int> a(n), b;
    for (int i = 0; i < n; i++){
      cin >> a[i];
      mp[a[i]]++;
    }
    int x = n / k;
    for (auto [f, s] : mp){
      b.push_back(s);
    }
    sort(b.rbegin(), b.rend());
    for (int i = 0; i < b.size() && i < k; i++){
      if (b[i] >= x) continue;
      ans += (x - b[i]);
    }
    cout << ans << endl; //mx<<" "<<j<<endl;
  }
}