#include"cstdio"
#define DMAX 200001
using namespace std;
int main()
{
	freopen("padurari.in","r",stdin);freopen("padurari.out","w",stdout);
	int v[DMAX],n,k,a,b=0,i,m=0;bool t;
	scanf("%d%d",&n,&k);
	if(k!=n/2)
		for(i=1;i<=n;i++)
		{
			scanf("%d",&a);
			v[i]=a-b;
			b=a;
		}
	else
	{
		for(i=1;i<=n;i++)
		{
			scanf("%d",&a);
			v[i]=a-b;
			b=a;
			if(!(i&1))
				m+=v[i];
		}
		printf("%d",m);
		return 0;
	}
	a=0;v[1]=1000000001;
	for(;k;--k)
	{
		m=1;
		for(i=2;i<=n;i++)
			if(v[m]>v[i]&&v[i]!=-1)
				m=i;
		a+=v[m];
		v[m]=v[m+1]=-1;
		if(m!=2)
			v[m-1]=-1;
	}
	printf("%d",a);
}