#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
ll dp[3030][3030];
ll a[3030];
ll s[3030];
const ll INF=1e18;
int main()
{
	int n, k, m; cin>>n>>k>>m;
	for(int i=0; i<n; i++){
		cin>>a[i];
		s[i+1]=s[i]+a[i];
	}
	for(int i=0; i<=n; i++) for(int j=0; j<=k; j++) dp[i][0]=-INF;
	dp[0][0]=0;
	for(int j=0; j<k; j++){
		vector<ll> v1(n+1), v2(n+1);
		for(int i=0; i<=n; i++){
			v1[i]=dp[i][j]-s[i];
			v2[i]=dp[i][j]+s[i];
		}
		deque<int> deq;
		deq.push_back(0);
		for(int i=1; i<=n; i++){
			while(!deq.empty() && deq.front()<i-m) deq.pop_front();
			if(!deq.empty()) dp[i][j+1]=max(dp[i][j+1], v1[deq.front()]+s[i]);
			while(!deq.empty() && v1[deq.back()]<=v1[i]) deq.pop_back();
			deq.push_back(i);
		}
		deq.clear();
		deq.push_back(0);
		for(int i=1; i<=n; i++){
			while(!deq.empty() && deq.front()<i-m) deq.pop_front();
			if(!deq.empty()) dp[i][j+1]=max(dp[i][j+1], v2[deq.front()]-s[i]);
			while(!deq.empty() && v2[deq.back()]<=v2[i]) deq.pop_back();
			deq.push_back(i);
		}
	}
	cout<<dp[n][k]<<endl;
	return 0;
}