#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int, ll> P;
#define yn {puts("YES");}else{puts("NO");}
#define MAX_N 200005

int main() {
    ll n, k, m;
    ll a[n];
    rep(i,n)cin >> a[i];

    ll sum[n+1] = {};
    drep(i,n) sum[i] = sum[i+1] + a[i];

    ll dp[k+1][n];
    ll INF = 1001001001001001001;
    rep(i,k+1){
        rep(j,n){
            dp[i][j] = -INF;
        }
    }
    dp[0][0];

    srep(i,1,k+1){
        deque<P> plus, minus;

        rep(j,n){
            // 前を削除(pop_front)
            if(!plus.empty() && plus[0].first < i - m){
                plus.pop_front();
            }
            if(!minus.empty() && minus[0].first < i - m){
                minus.pop_front();
            }

            if(j == 0){
                ;
            }else{
                dp[i][j] = max(dp[i][j], plus[0].second - sum[j+1]);
                dp[i][j] = max(dp[i][j], minus[0].second + sum[j+1]);
            }
            
            // 後ろから削除(pop_back)
            ll tmp1 = dp[i-1][j] + sum[j+1];
            while(!plus.empty() && plus[plus.size()-1].second < tmp1){
                plus.pop_back();
            }
            // 挿入(push_back)
            plus.push_back(P(i,tmp1));

            ll tmp2 = dp[i-1][j] - sum[j+1];
            while(!minus.empty() && minus[minus.size()-1].second < tmp2){
                minus.pop_back();
            }
            minus.push_back(P(tmp2,i));

        }
    }

    ll ans = dp[k][n-1];

    cout << ans << endl;
    return 0;
}