#pragma GCC optimize("Ofast")
#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define f0r(i, n) for (auto i = 0; i < (n); ++i)
#define fnr(i, n, k) for (auto i = (n); i < (k); ++i)
#define all(v) (v).begin(), (v).end()
#define pb push_back
#define F first
#define S second
#define ctn(x) cout << x << '\n'
#define forl(a, l) for (auto a : l)
#define ctl(l) for (auto &a : (l)) cout << a << ' '; cout << endl;
#define lb(v, x) (lower_bound(all(v), x) - begin(v))
#define ub(v, x) (upper_bound(all(v), x) - begin(v))
#define pq priority_queue
template <class T>
using V = vector<T>;
using ll = long long;
using vi = V<int>;
using vl = V<ll>;
using pi = pair<int, int>;
using ti = tuple<int, int, int>;
using Adj = V<vi>;
using vvi = V<vi>;
using db = long double;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int K, N;
cin >> N >> K;
vi A(N);
vl pf(N+1);
f0r(i, N) {
cin >> A[i];
pf[i+1] = pf[i] + A[i];
}
db lo = 0, hi = 1e9;
V<pair<db, int>> dp(N+1);
db ans = 0;
f0r(_, 100) {
db m = (lo+hi)/2; // lambda
dp.assign(N+1, {0, 0});
pair<db, int> mx{0, 0};
fnr(i, 1, N+1) {
dp[i] = max(dp[i-1], { mx.F+pf[i] - m, mx.S+1 });
mx = max(mx, {dp[i].F - pf[i], dp[i].S});
}
if (dp[N].S <= K) { // reduce lambda
hi = m;
ans = max(ans, (dp[N].F + dp[N].S * m));
} else lo = m;
}
ctn((ll)ans);
}
