#include<bits/stdc++.h>
using namespace std;
using LL=long long;
using ULL=unsigned long long;
#define rep(i,n) for(int i=0; i<(n); i++)

const LL INF=1000000000000000;

int N,K,M;
LL A[3001][2];
LL dp[3001][3001][2];
deque<int> dpw[3001][2];

int main(){
	cin>>N>>K>>M;
	rep(i,N) cin>>A[i][0]; A[N][0]=0;
	for(int i=N-1; i>=0; i--) A[i][0]+=A[i+1][0];
	rep(i,N+1) A[i][1]=-A[i][0];

	rep(t,2) rep(i,N+1) rep(k,K+1) dp[k][i][t]=-INF;
	rep(t,2) dp[0][0][t]=A[0][t];
	rep(t,2) rep(k,K+1) dpw[k][t]={0};

	rep(i,N) rep(k,K){
		LL tmp = -INF;
		rep(t,2){
			if(dpw[k][t].size()) if(dpw[k][t].front()<=i-M) dpw[k][t].pop_front();
			if(dpw[k][t].size()) tmp=max(tmp,dp[k][dpw[k][t].front()][t]-A[i+1][t]);
		}
		rep(t,2){
			dp[k+1][i+1][t]=tmp+A[i+1][t];
			while(dpw[k+1][t].size()) if(dp[k+1][dpw[k+1][t].back()][t]<=dp[k+1][i+1][t]) dpw[k+1][t].pop_back(); else break;
			dpw[k+1][t].push_back(i+1);
		}
	}

	cout<<dp[K][N][0]<<endl;

	return 0;
}