#include <iostream>
#include <algorithm>
#include <vector>
#include <math.h>
#include <cstdlib>
#define ll long long
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define inf -1e18
#define fi first
#define se second
using namespace std;
typedef pair <ll, int> li;
const int N = 3e5 + 9, M = 2e3 + 9;
int n, k;
ll a[N], pre[N], dp[M][M];
void sub1(){
for (int i = 1; i <= k; ++i){
ll cur = 0;
for (int j = 1; j <= n; ++j) {
cur = max(cur, dp[i-1][j] - pre[j]);
dp[i][j] = max(dp[i][j-1], cur + pre[j]);
}
}
cout << dp[k][n];
}
pair<ll, int> f[N];
void maximize(li &a, li b){
if (a.fi < b.fi) a = b;
if (a.fi == b.fi && a.se > b.se) a = b;
}
li calc(ll cost){
li best = {0, 0};
for (int i = 1; i <= n; ++i) {
f[i] = f[i-1];
maximize(f[i], {pre[i] + best.fi - cost , best.se + 1});
maximize(best, {f[i].fi - pre[i], f[i].se});
}
//f[n].se *= -1;
return f[n];
}
/// code WA
void sub2(){
ll lo = -1e18, hi = 1e18, ans = 0;
while (lo <= hi) {
ll mid = lo + hi >> 1;
li tmp = calc(mid);
if (tmp.se <= k) {
hi = mid - 1;
ans = max(ans, tmp.fi + mid*tmp.se);
} else lo = mid + 1;
}
cout << ans;
}
/// code AC
//void sub2(){
// ll lo = -1e18, hi = 1e18, ans = 0;
// while (lo < hi) {
// ll mid = lo + hi >> 1;
// li tmp = calc(mid);
// if (tmp.se <= k) {
// hi = mid;
// } else lo = mid + 1;
// }
// li tmp = calc(lo);
// cout << tmp.fi + k*lo;
//}
int main(){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
// freopen("nhap.inp", "r", stdin);
// freopen("xuat.out", "w", stdout);
cin >> n >> k;
FOR(i, 1, n) {
cin >> a[i];
pre[i] = pre[i-1] + a[i];
}
// if (max(k, n) <= 2000) sub1(); else
sub2();
return 0;
}
