#include <bits/stdc++.h>
using namespace std;
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
long long rand(long long l, long long r) {
return uniform_int_distribution<long long>(l, r)(rd);
}
#define int long long
#define pussy pair<__int128, int>
const int oo = 3e14 + 5;
const int N = 3e5 + 5;
int n, k, a[N];
pussy d[N][2];
pussy dp(int lambda) {
for (int i = 1; i <= n; ++i) {
for (int j = 0; j < 2; ++j) {
// dont take
d[i][j] = d[i - 1][0];
// take new segment
d[i][j] = max(d[i][j], {d[i - 1][1].first + a[i] - lambda, d[i - 1][1].second + 1});
// continue current segment
if (j) d[i][j] = max(d[i][j], {d[i - 1][1].first + a[i], d[i - 1][1].second});
}
}
return d[n][0];
}
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#ifdef LOCAL
// freopen("TEST.inp", "r", stdin);
// freopen("TEST.out", "w", stdout);
#else
// freopen("TEST.inp", "r", stdin);
// freopen("TEST.out", "w", stdout);
#endif
cin >> n >> k;
for (int i = 1; i <= n; ++i) {
cin >> a[i];
}
int l = -oo, r = oo, cut = -oo;
while (l <= r) {
int mid = l + (r - l) / 2;
auto [sum, cnt] = dp(mid);
if (cnt >= k) {
cut = mid;
l = mid + 1;
}
else r = mid - 1;
}
// cerr << "DB>> " << cut << '\n';
int ans = 0;
if (cut >= 0) {
auto [sum, cnt] = dp(cut);
ans = sum + k * cut;
}
else {
auto [sum, cnt] = dp(0);
ans = sum;
}
cout << ans << '\n';
return 0;
}
