#include <cstdio>
#include <iostream>
#include <string>
#include <sstream>
#include <stack>
#include <algorithm>
#include <cmath>
#include <queue>
#include <map>
#include <set>
#include <cstdlib>
#include <bitset>
#include <tuple>
#include <assert.h>
#include <deque>
#include <bitset>
#include <iomanip>
#include <limits>
#include <chrono>
#include <random>
#include <array>
#include <unordered_map>
#include <functional>
#include <complex>
#include <numeric>
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
//constexpr long long MAX = 5100000;
constexpr long long INF = 1LL << 60;
constexpr int inf = 1000000007;
//constexpr long long mod = 1000000007LL;
constexpr long long mod = 998244353LL;
const long double PI = acos((long double)(-1));

using namespace std;
typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;


int main()
{
    /*
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    */

    int n, k, m; scanf("%d %d %d", &n, &k, &m);
    vector<ll> a(n); for (int i = 0; i < n; i++) scanf("%lld", &a[i]);
    vector<ll> sum(n + 1); for (int i = 0; i < n; i++) sum[i + 1] = sum[i] + a[i];
    vector<vector<ll>> dp(n + 1, vector<ll>(k + 1, -INF));
    vector<deque<pair<int, ll>>> dq1(k + 1), dq2(k + 1);
    dq1[0].emplace_back(0, 0);
    dq2[0].emplace_back(0, 0);
    dp[0][0] = 0;
    for (int i = 0; i < n; i++) {
        for (int j = 1; j <= k; j++) {
            ll mx1 = -INF;
            ll mx2 = -INF;
            while (!dq1[j - 1].empty() and dq1[j - 1].front().first < i + 1 - m) dq1[j - 1].pop_front();
            while (!dq2[j - 1].empty() and dq2[j - 1].front().first < i + 1 - m) dq2[j - 1].pop_front();
            if (!dq1[j - 1].empty()) mx1 = dq1[j - 1].front().second;
            if (!dq2[j - 1].empty()) mx2 = dq2[j - 1].front().second;
            chmax(dp[i + 1][j], mx1 - sum[i + 1]);
            chmax(dp[i + 1][j], mx2 + sum[i + 1]);
        }
        for (int j = 0; j <= k; j++) {
            while (!dq1[j].empty() and dq1[j].back().second < dp[i + 1][j] + sum[i + 1]) dq1[j].pop_back();
            while (!dq2[j].empty() and dq2[j].back().second < dp[i + 1][j] - sum[i + 1]) dq2[j].pop_back();
            dq1[j].emplace_back(i + 1, dp[i + 1][j] + sum[i + 1]);
            dq2[j].emplace_back(i + 1, dp[i + 1][j] - sum[i + 1]);
        }
    }
    cout << dp[n][k] << endl;
    return 0;
}