#include <bits/stdc++.h>
#define be(v) (v).begin(),(v).end()
#define pb(q) push_back(q)
typedef long long ll;
using namespace std;
const ll mod=1000000007, INF=(1LL<<60);
#define doublecout(a) cout<<fixed<<setprecision(10)<<a<<endl;

void chmax(ll &a, ll b){a = max(a, b);}
int main() {
    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(false);
    ll n, k, m;
    cin >> n >> k >> m;
    vector<ll> a(n+1,0);
    for(int i=0;i<n;i++){
    	cin >> a[i];
    }
    for(int i = n - 1;i>=0;i--){
    	a[i] += a[i+1];
    }
    vector<deque<pair<int, ll> > > dqp(k+1), dqm(k+1);
    dqp[0].push_back({-1, a[0]});
    dqm[0].push_back({-1, -a[0]});
    vector<vector<ll> > dp(n+1, vector<ll> (k+1, 0));
    for(int i=0;i<n;i++){
    	for(int j=0;j<=k;j++) dp[i+1][j] = 0;
    	for(int j=k-1;j>=0;j--){
    		while(!dqp[j].empty() && dqp[j].front().first < i-m) dqp[j].pop_front();
    		while(!dqm[j].empty() && dqm[j].front().first < i-m) dqm[j].pop_front();
    		if(!dqp[j].empty()) chmax(dp[i+1][j+1], dqp[j].front().second - a[i + 1]);
    		if(!dqm[j].empty()) chmax(dp[i+1][j+1], dqm[j].front().second + a[i + 1]);
    		if (j + 1 < k) {
                while (!dqp[j + 1].empty() && dqp[j + 1].back().second <= dp[i + 1][j + 1] + a[i + 1]) dqp[j + 1].pop_back();
                while (!dqm[j + 1].empty() && dqm[j + 1].back().second <= dp[i + 1][j + 1] - a[i + 1]) dqm[j + 1].pop_back();
                dqp[j + 1].emplace_back(i, dp[i + 1][j + 1] + a[i + 1]);
                dqm[j + 1].emplace_back(i, dp[i + 1][j + 1] - a[i + 1]);
            }
    	}
    }
    cout << dp[n][k] << endl;
    return 0;
}