#include <iostream>
#include <vector>
#include <climits>
using namespace std;
int n, k;
vector<int> a;
vector<vector<pair<long long, long long> > > DP;
pair<long long, long long> dp(long long lambda)
{
DP[0][0] = { 0, 0 };
for (int i = 1; i <= n; i++)
{
DP[i][0] = max(DP[i - 1][0], DP[i - 1][1]);
DP[i][1] = max(
make_pair(DP[i-1][0].first + a[i] - lambda, DP[i-1][0].second + 1),
make_pair(DP[i - 1][1].first + a[i], DP[i - 1][1].second)
);
}
return max(DP[n][0], DP[n][1]);
}
int main()
{
cin >> n >> k;
DP.resize(n + 1, vector<pair<long long, long long>>(2, { LLONG_MIN, 0 }));
a.resize(n + 1);
for (int i = 1; i <= n; i++)
{
cin >> a[i];
}
long long l = 0, r = 3e14, lambda;
while ( r - l > 1)
{
lambda = (l + r) / 2;
auto m = dp(lambda);
if (m.second > k) l = lambda;
else r = lambda;
}
auto megoldas = dp(r);
cout << megoldas.first + megoldas.second * r;
return 0;
}
