#include <iostream>
#include <vector>
#include <algorithm>
#include <climits>
using namespace std;
int main() {
int n, k;
cin >> n >> k;
vector<vector<int>> arr;
for (int i = 0; i < n; i++) {
int x;
cin >> x;
arr.push_back({x, x + 1});
}
sort(arr.begin(), arr.end());
vector<vector<int>> ans;
for (int i = 0; i < n; i++) {
if (ans.empty() || arr[i][0] > ans.back()[1]) {
ans.push_back(arr[i]);
} else {
ans.back()[1] = max(ans.back()[1], arr[i][1]);
}
}
while ((int)ans.size() > k) {
int mn = INT_MAX, idx = -1;
for (int i = 0; i < (int)ans.size() - 1; i++) {
int gap = ans[i + 1][0] - ans[i][1];
if (gap < mn) mn = gap, idx = i;
}
vector<int> merged = {min(ans[idx][0], ans[idx + 1][0]), max(ans[idx][1], ans[idx + 1][1])};
ans.erase(ans.begin() + idx);
ans.erase(ans.begin() + idx);
ans.insert(ans.begin() + idx, merged);
}
int total = 0;
for (auto& v : ans) total += v[1] - v[0];
cout << total << endl;
return 0;
}
