#include <bits/stdc++.h>
using namespace std;
using ll = long long;
pair<ll, int> best(pair<ll, int> L, pair<ll, int> R) {
if (L.first == R.first) return {L.first, min(L.second, R.second)};
return max(L, R);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
int n, k; cin>>n>>k;
vector<ll> a(n+1);
for (int i = 1; i<=n; i++) cin>>a[i];
auto f = [&] (ll x) -> pair<ll, int> {
vector<vector<pair<ll, int>>> dp(n+1, vector<pair<ll, int>>(2));
dp[0][0] = {0, 0};
dp[0][1] = {-1e18, 0};
for (int i = 1; i<=n; i++){
dp[i][0] = best(dp[i-1][0], dp[i-1][1]);
dp[i][1] = dp[i-1][1]; dp[i][1].first += a[i];
if (dp[i-1][0].first > dp[i][1].first || (dp[i-1][0].first == dp[i][1].first && dp[i-1][0].second<dp[i][1].second)) {
dp[i][1] = dp[i-1][0];
dp[i][1].first += a[i]-x;
dp[i][1].second++;
}
}
return best(dp[n][0], dp[n][1]);
};
ll l = 0, r = 1e9;
while(r-l>1){
ll mid = (l+r)/2;
auto p = f(mid);
if (p.second >= k) l = mid;
else r = mid;
}
auto p = f(l);
if (p.second<=k) cout<<p.first+p.second*l;
else cout<<0;
}
