#include <iostream> #include <iomanip> #include <cstring> #include <algorithm> #include <math.h> #include <queue> #include <functional> #include <map> #include <vector> #include <string> using namespace std; typedef long long ll; const ll MOD = 1000000007; int n, k; ll a[100005],b[100005]; ll ans; int main(void){ cin >> n >> k; ans = 0; for (int i = 0; i < n; i++) cin >> a[i]; sort(a, a + n); for (int i = 0; i < n - 1; i++){ b[i] = a[i + 1] - a[i]; ans += b[i]; } sort(b, b + n - 1); for (int i = n - 2; i >= n - k; i--){ ans -= b[i]; } cout << ans << endl; }