#include <iostream>
#include <string>
#include <deque>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <map>
#include <set>
#include <queue>
#include <fstream>
#include <stack>
#include <cmath>
#include <bitset>
#include <unordered_set>
#include <unordered_map>
#include <random>
#include <array>
#include <chrono>
#include <functional>
#include <numeric>
#include <complex>
using namespace std;
#define ll long long
#define ld long double
#define ull uint64_t
#define pll pair<ll, ll>
#define pii pair<int, int>
#define fst first
#define snd second
#define forn(i, n) for (int i = 1; i <= n; i++)
#define dforn(i, a, b) for (int i = a; i <= b; i++)
#define rforn(i, n) for (int i = n; i >= 1; i--)
#define rdforn(i, a, b) for (int i = b; i >= a; i--)
#define sforn(i, a, b, s) for (ll i = a; i <= b; i += s)
#define aforn(v, a) for (auto& v : a)
const int mod = 998244353;
const ld pi = acos(-1);
const ll N = 1e6;
const ll inf = 1e17;
const int iinf = 1 << 30;
const ld dinf = 1e10;
const double eps = 1e-10;
void solve() {
ll n, k;
cin >> n >> k;
vector<ll> a(n + 1);
forn(i, n) {
cin >> a[i];
}
auto calc = [&](ll lambda) {
vector<ll> dp(n + 1), cnt(n + 1);
ll best = 0, bcnt = 1;
forn(i, n) {
dp[i] = dp[i - 1];
cnt[i] = cnt[i - 1];
best += a[i];
if (best - lambda > dp[i]) {
dp[i] = best - lambda;
cnt[i] = bcnt;
}
if (dp[i] > best) {
best = dp[i];
bcnt = cnt[i] + 1;
}
}
return make_pair(dp[n], cnt[n]);
};
ll l = -1, r = 1e13;
while (r - l > 1) {
ll m = (l + r) >> 1;
pll f = calc(m);
if (f.snd <= k) {
r = m;
}
else {
l = m;
}
}
pll cur = calc(r);
ll ans = cur.fst + k * r;
cout << ans << '\n';
}
int main()
{
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int t = 1;
//cin >> t;
while (t--) solve();
return 0;
}
