#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#define ll long long
#define rep(i,n) for(ll i=0;i<(n);i++)
#define pll pair<ll,ll>
#define pq priority_queue
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define ios ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define lb(c,x) distance(c.begin(),lower_bound(all(c),x))
#define ub(c,x) distance(c.begin(),upper_bound(all(c),x))

using namespace std;

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;}

const ll INF=1e18;

int main(){
    ll n,k,m;
    cin >> n >> k >> m;
    vector<ll> a(n),s(n+1);
    rep(i,n){
        cin >> a[i];
    }
    rep(i,n){
        s[i+1]=s[i]+a[i];
    }
    vector<vector<ll>> dp(n+1,vector<ll>(k+1,-INF));
    vector<deque<pll>> dq1(k + 1), dq2(k + 1);
    dq1[0].emplace_back(0, 0);
    dq2[0].emplace_back(0, 0);
    dp[0][0]=0;
    for(ll i=1;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 - m) dq1[j - 1].pop_front(); //biの長さはm以下
            while (!dq2[j - 1].empty() and dq2[j - 1].front().first < i - m) dq2[j - 1].pop_front(); //biの長さはm以下
            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][j], mx1 - s[i]);
            chmax(dp[i][j], mx2 + s[i]);
        }
        for (int j = 0; j <= k; j++) {
            while (!dq1[j].empty() and dq1[j].back().second < dp[i][j] + s[i]) dq1[j].pop_back();
            while (!dq2[j].empty() and dq2[j].back().second < dp[i][j] - s[i]) dq2[j].pop_back();
            dq1[j].emplace_back(i, dp[i][j] + s[i]);
            dq2[j].emplace_back(i, dp[i][j] - s[i]);
        }
    }
    cout << dp[n][k] << endl;
    return 0;
}