#include <bits/stdc++.h>
using namespace std;
#define all(v) v.begin(),v.end()
#define pb push_back
#define ll long long
#define ld long double
#define fi first
#define se second
#define mk make_pair
typedef pair<ll,ll> pii;
const int maxn = 3e5 + 10;
const ll inf = 1e17;
ll a[maxn];
pii dp[maxn][2];
int n,k;
pii cal(ll cost)
{
for(int i = 1;i<=n;i++)
{
dp[i][0] = max(dp[i-1][0],dp[i-1][1]);
dp[i][1] = max( mk(dp[i-1][0].fi + a[i] - cost,dp[i-1][0].se+1),
mk(dp[i-1][1].fi + a[i], dp[i-1][1].se ));
}
return max(dp[n][0],dp[n][1]);
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
dp[0][1] = mk(-inf,0);
cin>>n>>k;
for(int i = 1;i<=n;i++)cin>>a[i];
ll l = 0,r = 1e13;
while(l<r)
{
ll mid = (l + r + 1)/2;
pii ans = cal(mid);
if(ans.se>k)l=mid;
else r = mid-1;
}
pii ans = cal(l+1);
cout<<ans.fi+ans.se * l;
return 0;
}
