include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

int main()
{
    int n, k, b = 1;
    cin >> n >> k;
    vector<int> a (n);
    vector<int> o;

    for (int i = 0; i < n; i++)
        cin >> a[i];

    sort(a.begin(), a.end());

    for (int i = 0; i < n; i++)
        if (!(binary_search(o.begin(), o.end(), a[i])))
            o.push_back(a[i]);

    for (int i = 0; i < o.size(); i++)
        if (count(a.begin(), a.end(), o[i]) > k)
            b++;

    cout << (o.size() * b * k - a.size()) << endl;

}