#include <bits/stdc++.h> using namespace std; int n, k; array<int, 100'000> visits; int main() { ios_base::sync_with_stdio(0); cin.tie(0); cin >> n >> k; vector<int> diffs; int result = n; for (int i = 0; i < n; i++) cin >> visits[i]; for (int i = 1; i < n; i++) diffs.push_back(visits[i] - visits[i - 1] - 1); sort(diffs.begin(), diffs.end()); for (int i = 0; i < n - k; i++) result += diffs[i]; cout << result << "\n"; }