#include<bits/stdc++.h>

using namespace std;

#define il inline

#define gc getchar()

#define ll long long

#define ri register int

#define rb register bool

#define rc register char

#define rp(i,x,y) for(ri i=x;i<=y;++i)

#define my(i,x,y) for(ri i=x;i>=y;--i)

#define lb(x) lower_bound(st+1,st+st_cnt+1,x)-st

const int N=+,inf=1e9;

int n,K,a[N],l[N],r[N],d[N];

ll as;

bool vis[N];

struct node{ll dat;int id;}tmp;

priority_queue<node>Q;

il int read()

{

    rc ch=gc;ri x=;rb y=;

    while(ch!='-' && (ch>'' || ch<''))ch=gc;

    if(ch=='-')ch=gc,y=;

    while(ch>='' && ch<='')x=(x<<)+(x<<)+(ch^''),ch=gc;

    return y?x:-x;

}

il bool operator < (node gd,node gs){return gd.dat>gs.dat;}

int main()

{

    //freopen("3620.in","r",stdin);freopen("3620.out","w",stdout);

    n=read();K=read();

    rp(i,,n-){d[i]=read();if(i){tmp=(node){a[i]=d[i]-d[i-],i};Q.push(tmp);l[i]=i-;r[i]=i+;}}

    r[]=;l[n]=n-;a[]=a[n]=inf;

    while(K--)

    {

        while(vis[Q.top().id])Q.pop();

        node nw=Q.top();Q.pop();ri pos=nw.id;

        as+=nw.dat;nw.dat=a[pos]=a[l[pos]]+a[r[pos]]-a[pos];Q.push(nw);

        vis[l[pos]]=vis[r[pos]]=;l[pos]=l[l[pos]];r[pos]=r[r[pos]];r[l[pos]]=pos;l[r[pos]]=pos;

    }

    printf("%lld\n",as);

    return ;

}