#include <iostream>
#include <vector>
#include <algorithm>
#include <climits>
using namespace std;
int main() {
int n, k, x;
cin >> n >> k;
vector<pair<int, int>> intervals;
while (n--) {
cin >> x;
intervals.emplace_back(x, x + 1);
}
sort(intervals.begin(), intervals.end());
vector<pair<int, int>> merged;
for (auto& [l, r] : intervals) {
if (merged.empty() || l > merged.back().second)
merged.emplace_back(l, r);
else
merged.back().second = max(merged.back().second, r);
}
while ((int)merged.size() > k) {
int min_gap = INT_MAX, idx = -1;
for (int i = 0; i + 1 < merged.size(); i++) {
int gap = merged[i + 1].first - merged[i].second;
if (gap < min_gap) min_gap = gap, idx = i;
}
pair<int, int> comb = {
min(merged[idx].first, merged[idx + 1].first),
max(merged[idx].second, merged[idx + 1].second)
};
merged.erase(merged.begin() + idx, merged.begin() + idx + 2);
merged.insert(merged.begin() + idx, comb);
}
int total = 0;
for (auto& [l, r] : merged) total += r - l;
cout << total << endl;
}
