#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N = 3e5 + 5;
ll n, k, a[N], p[N];
pair <ll, ll> solve(int lmb){
pair <ll, ll> mx = {0, 0};
vector <pair <ll, ll>> dp(n + 1);
for (int i = 1; i <= n; i++) {
dp[i] = max(dp[i - 1], {mx.first + p[i] - lmb, mx.second + 1});
mx = max(mx, {dp[i].first - p[i], dp[i].second});
}
dp[n].first += dp[n].second * lmb;
return dp[n];
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> k;
for (int i = 1; i <= n; i++) {
cin >> a[i];
p[i] = p[i - 1] + a[i];
}
ll l = 1, r = 1e9, mid = 0;
pair <ll, ll> ans = {0, 0};
while (l <= r) {
mid = l + (r - l) / 2;
ans = solve(mid);
if (ans.second > k) l = mid + 1;
else if (ans.second <= k) r = mid - 1;
}
cout << ans.first;
}
