#include<bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10, inf = 0x3f3f3f3f3f;
struct P{
	int val, l, r;
};
struct T{
	int id,sub;
	bool operator < (const T &t) const {
		return sub > t.sub;
	}
};
P p[N];
int a[N];
bool vis[N];
long long ans;
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0),cout.tie(0);
	int n, k;
	cin >> n >> k;
	priority_queue<T> heap;
	cin >> a[0];
	for (int i = 1; i < n; i ++){
		cin >> a[i];
		p[i].val = a[i] - a[i-1];
		p[i].l = i-1, p[i].r = i + 1;
		heap.push({i,p[i].val});
	}
	p[0].val = p[n].val = inf;
	for (int i = 1; i <= k; i ++){
		while(vis[heap.top().id]) heap.pop();
		T t = heap.top();
		heap.pop();
		ans += t.sub;
		int tl = p[t.id].l, tr = p[t.id].r;
		vis[tl] = vis[tr] = true;
		p[t.id].val = p[tl].val + p[tr].val - p[t.id].val;
		heap.push({t.id,p[t.id].val});
		p[t.id].l = p[tl].l, p[t.id].r = p[tr].r;
		p[p[t.id].l].r = t.id, p[p[t.id].r].l = t.id;
	}
	cout << ans;
	return 0;
}