#include "bits/stdc++.h"
using namespace std;
#define endl '\n'
#define debug(x) cerr << #x << " == " << (x) << '\n';
#define all(x) begin(x), end(x)
using ll = long long;
const int INF = 0x3f3f3f3f;
const ll LINF = 0x3f3f3f3f3f3f3f3fLL;
template<typename T>
bool chmin(T& x, T y) { return y < x ? (x = y, true) : false; }
template<typename T>
bool chmax(T& x, T y) { return x < y ? (x = y, true) : false; }
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int N, K;
cin >> N >> K;
vector<int> A(N);
for (auto& x : A) cin >> x;
auto f = [&](ll z) {
ll dpmax = 0, prefsum = 0, prefmax = 0;
int cnt_dpmax = 0, cnt_prefmax = 0;
for (auto x : A) {
prefsum += x;
ll dp = prefsum + prefmax - z;
if (chmax(dpmax, dp)) cnt_dpmax = 1 + cnt_prefmax;
if (chmax(prefmax, dpmax - prefsum)) cnt_prefmax = cnt_dpmax;
}
return pair(dpmax, cnt_dpmax);
};
const ll inf = 1e10;
ll L = 0, R = inf;
while (L < R) {
ll M = L + (R - L) / 2;
f(M).second <= K ? R = M : L = M + 1;
}
auto [a, b] = f(L);
ll ans = a + b * L;
cout << ans << endl;
exit(0);
}
