#include <bits/stdc++.h>
#define FOR(i, begin, end) for(int i = (begin); i < (end); i++)
#define FAST_IO ios_base::sync_with_stdio(0); cin.tie(nullptr); cout.tie(nullptr)
#define f first
#define s second
#define pb push_back
#define sz(x) ((int)((x).size()))
#define le(vec) vec[vec.size()-1]
#define all(x) (x).begin(), (x).end()
#define TSTS int ttt; cin >> ttt; while(ttt--) solve()
using namespace std;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef pair<long double, long double> pdd;
typedef map<int, int> mii;
typedef vector<int> vi;
typedef long double ld;
typedef long long ll;
const int INF=1e9, MOD=1e9+7, mod=998244353;
const ll LINF=1e18;
void setIO()
{
FAST_IO;
}
void setIO(string s)
{
FAST_IO;
freopen((s+".in").c_str(), "r", stdin);
freopen((s+".out").c_str(), "w", stdout);
}
#define int long long
const int N=3e5+10;
int n, k;
ll a[N], p[N];
pair<ll, int> dp[N];
bool can(ll x)
{
FOR(i, 0, n+1) dp[i]={0,0};
pair<ll, int> best={0,0};
FOR(i, 1, n+1)
{
dp[i]=max(dp[i-1], {best.f+a[i]-x+p[i],best.s+1});
best=max(best, {dp[i].f-p[i],dp[i].s});
}
return dp[n].s<=k;
}
ll build(ll x)
{
FOR(i, 0, n+1) dp[i]={0,0};
pair<ll, int> best={0,0};
FOR(i, 1, n+1)
{
dp[i]=max(dp[i-1], {best.f-x+p[i],best.s+1});
best=max(best, {dp[i].f-p[i],dp[i].s});
}
return dp[n].f+dp[n].s*x;
}
signed main()
{
setIO();
cin >> n >> k;
FOR(i, 1, n+1) cin >> a[i];
FOR(i, 1, n+1) p[i]=p[i-1]+a[i];
int l=-INF, r=INF;
while(l<r){
int m=(l+r)/2;
if(can(m)) r=m;
else l=m+1;
}
cout << build(l);
}
