#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define eb emplace_back
#define pu push
#define ins insert
#define fi first
#define se second
#define all(a) a.begin(),a.end()
#define bruh ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define fu(x,a,b) for (auto x=a;x<=b;x++)
#define fd(x,a,b) for (auto x=a;x>=b;x--)
#define int ll
using namespace std;
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
//mt19937 mt(chrono::steady_clock::now().time_since_epoch().count());
/*
Competitive Programming notes that I need to study & fix my dumbass self:
1. Coding:
- Always be sure to check the memory of arrays (maybe use vectors), for loops, I don't know
- Always try to maximize the memory if possible, even if you are going for subtasks
- Do not exploit #define int long long, it will kill you
2. Stress:
- Don't be cocky and think stressing with your dumbass brute-force solution will give you guaranteed AC.
- Always try generating big testcases and try if they run
3. Time management:
- Don't overcommit or undercommit, always spend a certain amount of time to think a problem, don't just look at it and say I'm fucked
- Do not spend too much time coding brute-force solutions, they should be easily-codable solutions that don't take up too much time
I hate offline because I am dumb
*/
typedef pair<int, int> ii;
const int N = 3e5+5;
const int mod = 1e9+7;
const int inf = 1e18;
using cd = complex<double>;
const long double PI = acos(-1);
int power(int a,int b) {ll x = 1;if (a >= mod) a%=mod; while (b) {if (b & 1) x = x*a % mod;a = a*a % mod;b>>=1;}return x;}
int n,k;
int a[N];
ii calc(int lmb)
{
ii dp[n][2];
dp[0][0] = {0,0}, dp[0][1] = {a[0]-lmb, 1};
for (int i = 1; i < n; i++)
{
dp[i][0] = max(dp[i-1][0], dp[i-1][1]);
dp[i][1] = max(make_pair(dp[i-1][1].fi + a[i], dp[i-1][1].se), make_pair(dp[i-1][0].fi + a[i] - lmb, dp[i-1][0].se + 1));
}
return max(dp[n-1][0], dp[n-1][1]);
}
void solve()
{
cin>>n>>k;
for (int i = 0; i < n; i++) cin>>a[i];
int l = 0, r = 1e18, ans = 0;
while (l <= r)
{
int mid = l+r>>1;
if (calc(mid).se <= k) ans = mid, r = mid-1;
else l = mid+1;
}
cout<<calc(ans).fi + ans * k;
}
/*
Go through the mistakes you usually make and revise your code, for god's sake...
*/
signed main()
{
bruh
//freopen("input.inp","r",stdin);
//freopen("output.inp","w",stdout);
int t = 1;
// cin>>t;
while (t--)
{
solve();
cout<<"\n";
}
}
