#include <bits/stdc++.h>
using namespace std;

const long long INF = -1e18;

int main() {

    int N, K, M;
    cin >> N >> K >> M;
    vector<long long> A(N + 1), prefix(N + 1);
    for (int i = 1; i <= N; i++) {
        cin >> A[i];
        prefix[i] = prefix[i - 1] + A[i];
    }

    vector<long long> dp_prev(N + 1, INF);
    dp_prev[0] = 0;

    for (int k = 1; k <= K; k++) {
        vector<long long> dp_curr(N + 1, INF);
        deque<pair<long long, int>> dq_pos, dq_neg;

        for (int i = 1; i <= N; i++) {
            
            while (!dq_pos.empty() && dq_pos.front().second < i - M)
                dq_pos.pop_front();
            while (!dq_neg.empty() && dq_neg.front().second < i - M)
                dq_neg.pop_front();

            
            if (i - 1 >= 0) {
                long long val_pos = dp_prev[i - 1] + prefix[i - 1];
                while (!dq_pos.empty() && dq_pos.back().first <= val_pos)
                    dq_pos.pop_back();
                dq_pos.emplace_back(val_pos, i - 1);

                long long val_neg = dp_prev[i - 1] - prefix[i - 1];
                while (!dq_neg.empty() && dq_neg.back().first <= val_neg)
                    dq_neg.pop_back();
                dq_neg.emplace_back(val_neg, i - 1);
            }

            
            if (!dq_pos.empty())
                dp_curr[i] = max(dp_curr[i], dq_pos.front().first - prefix[i]);
            if (!dq_neg.empty())
                dp_curr[i] = max(dp_curr[i], dq_neg.front().first + prefix[i]);
        }

        dp_prev = dp_curr;
    }

    cout << dp_prev[N] << endl;
    return 0;
}