#include <bits/stdc++.h> using namespace std; typedef long long ll; void solve() { int N, K; cin >> N >> K; int ans = N; vector<int> T(N); for (auto& t : T) cin >> t; vector<int> diff; for (int i = 0; i+1 < N; i++) diff.push_back(T[i+1] - T[i] - 1); sort(diff.begin(), diff.end()); for (auto it : diff) ans += it; for (int i = diff.size()-1; K > 1 && i > 0; --K, --i) { ans -= diff[i]; } cout << ans; } int main() { ios_base::sync_with_stdio(false); cin.tie(0); solve(); }