// Author : Udynamo
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<int, null_type, std::less<int>, rb_tree_tag,
tree_order_statistics_node_update> pbds;
#define int long long
#define mk make_pair
#define ff first
#define ss second
#define pb push_back
#define vi vector<int>
#define vpi vector<pair<int,int>>
#define all(x) x.begin(),x.end()
using namespace std;
template<typename T>
istream& operator>>(istream &is, vector<T> &v) {
for (auto &x : v) is >> x;
return is;
}
const int INF = 1e18;
void UNsolve() {
int n, kk;
cin >> n >> kk;
vi a(n);
cin >> a;
auto solve_lambda = [&](int lmb){
vpi dp(n, {-INF, 0});
dp[0] = max(mk(0LL,0LL), mk(a[0] + lmb,1LL));
for(int i = 1; i < n; i++){
auto [val, cnt] = dp[i - 1];
dp[i] = max({
dp[i - 1],
mk(val + a[i], cnt),
mk(a[i] + lmb, cnt + 1)
});
}
return dp.back();
};
int l = 0, r = 1e9, ans = 0;
while(l <= r){
int mid = (l + r) >> 1;
auto [val, cnt] = solve_lambda(mid);
if(cnt >= kk){
ans = mid;
r = mid - 1;
}else{
l = mid + 1;
}
}
auto [val, cnt] = solve_lambda(ans);
cout << val - kk * ans << endl;
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
UNsolve();
return 0;
}
