///0-0 : what is your motivation, quan606303?
///quan606303 : Hutao
/*idea :
*/
#include <bits/stdc++.h>
#define int long long
#define ll long long
#define INTMAX INT_MAX
#define INTMIN INT_MIN
#define LONGMAX LLONG_MAX
#define LONGMIN LLONG_MIN
#define fi first
#define se second
#define memfull(a,b) memset(a,b,sizeof(a));
#define endl '\n'
#define file(a) freopen(a".inp","r",stdin); freopen(a".out","w",stdout);
using namespace std;
const int MOD=1e9+7;
const int maxn=2e5+7;;
int n,k,a[maxn],pre[maxn];
pair<int,int> dp[maxn][2];
pair<int,int> sub1(int pen)
{
dp[1][0]={0,0};
dp[1][1]={-pre[0]-pen,1};
for (int i=2;i<=n;i++)
{
dp[i][1]=max(dp[i-1][1],make_pair(dp[i-1][0].fi-pre[i-1]-pen,dp[i-1][0].se+1));
dp[i][0]=max(dp[i-1][0],make_pair(dp[i-1][1].fi+pre[i],dp[i-1][1].se));
}
return dp[n][0];
}
int32_t main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
// file("MUABANCO");
cin>>n>>k;
for (int i=1;i<=n;i++)cin>>a[i];
for (int i=1;i<=n;i++)pre[i]=pre[i-1]+a[i];
int l=0,r=1e18,ans=0;
while (l<=r)
{
int mid=(l+r)/2;
pair<int,int> cnt=sub1(mid);
if (cnt.se<=k)
{
r=mid-1;
ans=cnt.fi+cnt.se*mid;
}
else l=mid+1;
}
cout<<ans;
return 0;
}
