#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; i++)
#define rep2(i, x, n) for(int i = x; i <= n; i++)
#define rep3(i, x, n) for(int i = x; i >= n; i--)
#define elif else if
#define sp(x) fixed << setprecision(x)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const ll MOD = 1e9+7;
//const ll MOD = 998244353;
const int inf = (1<<30)-1;
const ll INF = (1LL<<60)-1;
const ld EPS = 1e-10;
template<typename T> bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;};
template<typename T> bool chmin(T &x, const T &y) {return (x > y)? (x = y, true) : false;};

int main(){
    int N, K, M;
    cin >> N >> K >> M;
    vector<ll> A(N);
    rep(i, N) cin >> A[i];
    ll dp[N+1][K+1];
    fill(dp[0], dp[N+1], -INF);
    dp[0][0] = 0;
    priority_queue<pli> que[2];
    ll sum[2];
    rep2(j, 1, K){
        sum[0] = sum[1] = 0;
        rep(i, N){
            rep(k, 2) que[k].push(pli(dp[i][j-1]-sum[k], i));
            sum[0] += A[i], sum[1] -= A[i];
            rep(k, 2){
                while(!que[k].empty()){
                    if(que[k].top().second <= i-M) que[k].pop();
                    else break;
                }
                chmax(dp[i+1][j], que[k].top().first+sum[k]);
            }
        }
        rep(k, 2) while(!que[k].empty()) que[k].pop();
    }
    cout << dp[N][K] << endl;
}