#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#define DEBUG(...) debug(#__VA_ARGS__, __VA_ARGS__)
#else
#define DEBUG(...) 6
#endif
template<typename T, typename S> ostream& operator << (ostream &os, const pair<T, S> &p) {return os << "(" << p.first << ", " << p.second << ")";}
template<typename C, typename T = decay<decltype(*begin(declval<C>()))>, typename enable_if<!is_same<C, string>::value>::type* = nullptr>
ostream& operator << (ostream &os, const C &c) {bool f = true; os << "["; for (const auto &x : c) {if (!f) os << ", "; f = false; os << x;} return os << "]";}
template<typename T> void debug(string s, T x) {cerr << s << " = " << x << "\n";}
template <typename T, typename... Args> void debug(string s, T x, Args... args) {for (int i=0, b=0; i<(int)s.size(); i++) if (s[i] == '(' || s[i] == '{') b++; else
if (s[i] == ')' || s[i] == '}') b--; else if (s[i] == ',' && b == 0) {cerr << s.substr(0, i) << " = " << x << " | "; debug(s.substr(s.find_first_not_of(' ', i + 1)), args...); break;}}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n, k;
cin >> n >> k;
vector<int> a(n);
for (int i=0; i<n; i++)
cin >> a[i];
auto solve = [&] (long long c) -> pair<bool, long long> {
vector<long long> pref(n + 1);
for (int i=0; i<n; i++)
pref[i+1] = a[i] + pref[i];
vector<long long> dp(n + 1);
vector<int> cnt(n + 1);
dp[0] = 0;
int mx = 0;
for (int i=0; i<n; i++) {
dp[i+1] = dp[i];
cnt[i+1] = cnt[i];
if (dp[mx] + pref[i+1] - pref[mx] - c > dp[i]) {
dp[i+1] = dp[mx] + pref[i+1] - pref[mx] - c;
cnt[i+1] = cnt[mx] + 1;
}
if (dp[i+1] - pref[i+1] > dp[mx] - pref[mx])
mx = i + 1;
}
return {cnt[n] <= k, dp[n] + c * cnt[n]};
};
long long l = 0, r = 1e18;
while (l < r) {
long long m = (l + r) / 2;
if (solve(m).first)
r = m;
else
l = m + 1;
}
cout << solve(l).second << "\n";
return 0;
}
