#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int MAX = 300000;
const ll INF = (ll)300000 * 1000000000;
int n, k, A[MAX + 1];
pair<ll, ll> dp[MAX + 1][2];
pair<ll, ll> better(pair<ll, ll> a, pair<ll, ll> b) {
if (a.first == b.first){ return (a.second < b.second ? a : b); }
return (a.first > b.first ? a : b);
}
pair<ll, ll> solveLambda(ll lmb){
dp[0][0] = {0, 0};
dp[0][1] = {-INF, 0};
for (int i = 1; i <= n; i++) {
dp[i][0] = better(dp[i - 1][0], dp[i - 1][1]);
dp[i][1] =
better({dp[i - 1][0].first + A[i] - lmb, dp[i - 1][0].second + 1},
{dp[i - 1][1].first + A[i], dp[i - 1][1].second});
}
return better(dp[n][0], dp[n][1]);
}
int main() {
cin >> n >> k;
for (int i = 1; i <= n; i++) cin >> A[i];
ll lo = 0, hi = INF;
while (lo < hi) {
ll mid = (lo + hi) / 2;
solveLambda(mid).second <= k ? hi = mid : lo = mid + 1;
}
cout << solveLambda(lo).first + lo * k << endl;
}
