#include "bits/stdc++.h"
using namespace std;
#define int long long
signed main () {
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n, k;
cin >> n >> k;
vector <int> a(n);
for(int i = 0; i < n; i ++) cin >> a[i];
sort(a.begin(), a.end());
int ans = 1e9;
for(int mask = 0; mask < (1 << n); mask ++) {
if(__builtin_popcount(mask) != k) continue;
if(mask % 2 != 1) continue;
int prev = a[0], cnt = 0;
for(int i = 1; i < n; i ++) {
if(mask & (1 << i)) {
cnt += a[i-1]+1-prev;
prev = a[i];
}
}
cnt += a[n-1]+1-prev;
ans = min(ans, cnt);
}
cout << ans;
return 0;
}
