#include <iostream>
#include <bits/stdc++.h>
using namespace std;

int main(){
int n, k, d[101] = {}, a, max_sum_n = 0, quan_bl, quan_ano = 0;
cin >> n >> k;
for(int i = 1; i <= n; i++){
    cin >> a;
    d[a]++;
    max_sum_n = max(d[a], max_sum_n);
    if(d[a] == 1){
        quan_ano++;
    }
}
if(max_sum_n % k   == 0){
    quan_bl = max_sum_n / k;
}
else{
    quan_bl = (max_sum_n / k) + 1;
}
//cout << quan_bl << endl << quan_ano << endl;
cout << (quan_bl * quan_ano * k) - n;

return 0;
}