#include<iostream>
#include<string>
#include<iomanip>
#include<cmath>
#include<vector>
#include<algorithm>
#include<utility>
#include<queue>

using namespace std;

#define int long long
#define endl "\n"

constexpr long long INF = (long long)1e18;
constexpr long long MOD = 1'000'000'007; 

struct fast_io {
	fast_io(){
		std::cin.tie(nullptr);
		std::ios::sync_with_stdio(false);
	};
} fio;


signed main(){
	cout<<fixed<<setprecision(10);
	
	int N, K, M;
	vector<int> A;
	vector<int> sum;
	vector<vector<int>> dp;
	vector<deque<int>> q, q2;
	cin>>N>>K>>M;
	
	A.resize(N);
	dp.resize(N+1, vector<int>(K+1, -INF));
	sum.resize(N+1);
	
	for(int i = 0; i < N; i++){
		cin>>A[i];
	
		sum[i+1] = sum[i] + A[i];
		
		if(i < M) dp[i][1] = abs(sum[i+1]);
	}

	for(int j = 2; j <= K; j++){
		deque<pair<int,int>> q, q2;
		
		for(int i = j-1; i < N; i++){
			int num = dp[i-1][j-1] - sum[i];
			int num2 = dp[i-1][j-1] + sum[i];
			
			while(q.size() && q.back().second < num) q.pop_back();
			q.emplace_back(i, num);
			while(q.size() && q.front().first < i - M + 1) q.pop_front();
			
			while(q2.size() && q2.back().second < num2) q2.pop_back();
			q2.emplace_back(i, num2);
			while(q2.size() && q2.front().first < i - M + 1) q2.pop_front();
			
			dp[i][j] = max(q.front().second + sum[i+1], q2.front().second - sum[i+1]);
		}
	}

	
	cout<<dp[N-1][K]<<endl;
	
	return 0;
}