#include<bits/stdc++.h>
#define int long long
#define double long double
#define PB push_back
#define maxn 300007
#define bit(x,i) ((x>>i)&1)
#define S second
#define F first
#define MP make_pair
using namespace std;
typedef pair<int,int> pii;
typedef pair<double,double> pdd;
typedef pair<double,int> pdi;
const int inf = 1e9*3e5;
const int mod = 1e9+7;
const double PI = acos(-1);
const double eps = 1e-3;
int n,k,a[maxn];
pdi f[maxn][2];
void readData(){
cin>>n>>k;
for (int i=1;i<=n;i++) cin>>a[i];
}
bool check(double dak){
f[0][0]={0,0};
f[0][1]={-inf,0};
for (int i=1;i<=n;i++){
f[i][0]=max(f[i-1][0],f[i-1][1]);
f[i][1]=max((pdi){f[i-1][1].F+a[i],f[i-1][1].S},(pdi){f[i-1][0].F+a[i]-dak,f[i-1][0].S+1});
}
int mim=max(f[n][0],f[n][1]).S;
return mim>=k;
}
void solve(){
double l=0,r=inf,dak;
while (l+eps<r){
double mid=(l+r)/2;
if (check(mid)) l=mid;
else r=mid;
}
dak=l;
check(dak);
int ans=round(dak*k+max(f[n][0],f[n][1]).F);
cout<<ans;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
readData();
solve();
return 0;
}
