// Designed by Mahmud Isali #pragma GCC optimize("O3,unroll-loops") #include <bits/stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> using namespace std; using namespace __gnu_pbds; using pii = pair<int,int>; using dbl = double; #define int long long #define pb push_back #define F first #define S second #define all(x) (x).begin(), (x).end() #define rall(x) (x).rbegin(), (x).rend() #define fastio() ios::sync_with_stdio(false); cin.tie(nullptr); #define endl '\n' #define newl cout << endl #define spl debug(string(100,'-')) template<class T>using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; template<class T>using ordered_multiset = tree<pair<T,int>, null_type, less<pair<T,int>>, rb_tree_tag, tree_order_statistics_node_update>; template<class T>int sz(const T& x) { return (int)x.size(); } template<class T>int upper_index(const vector<T> &a, const T &x) {return (int)(upper_bound(all(a), x) - a.begin());} template<class T>int lower_index(const vector<T> &a, const T &x) {return (int)(lower_bound(all(a), x) - a.begin());} mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count()); const int INF = (int)4e18; const int MOD = 998244353; const int MOD2 = 998244353; const int N = 1e6 + 5; const dbl EPS = 1e-12; void solve(){ int n,k; cin >> n >> k; int need = n - k; vector<int> v; int sum = 0; int lst = -1; for(int i = 1; i <= n; i++) { int x; cin >> x; sum++; if(lst == -1) {lst = x;continue;} v.pb(x - lst - 1); lst = x; } sort(all(v)); for(int i = 0; i < need; i++) sum += v[i]; cout << sum; } signed main() { fastio(); int t = 1; // cin >> t; for (int i = 1; i <= t; i++) { // cout << "Test Case: " << i << endl; solve(); } }