#include<iostream>
using namespace std;
#include<vector>
#include<functional>
template<typename T>
struct lazysegtree{
	using F=function<T(T,T)>;
	using G=function<T(T,T,int,int)>;
	const F calcfn,lazycalcfn;
	const G updatefn;
	int n;
	T defvalue,lazydefvalue;
	vector<T>dat,lazy;
	vector<bool>lazyflag;
	lazysegtree(int n_=0,T defvalue_=0,
		const F calcfn_=[](T a,T b){return a+b;},
		const F lazycalcfn_=[](T a,T b){return a+b;},
		const G updatefn_=[](T a,T b,int l,int r){return a+b*(r-l);},
		T lazydefvalue_=0
	):defvalue(defvalue_),lazydefvalue(lazydefvalue_),
		calcfn(calcfn_),lazycalcfn(lazycalcfn_),updatefn(updatefn_)
	{
		n=1;
		while(n<n_)n<<=1;
		dat.assign(2*n-1,defvalue);
		lazy.assign(2*n-1,lazydefvalue);
		lazyflag.assign(2*n-1,false);
	}
	void copy(const vector<T>&v)
	{
		for(int i=0;i<v.size();i++)dat[i+n-1]=v[i];
		for(int i=n-2;i>=0;i--)dat[i]=calcfn(dat[2*i+1],dat[2*i+2]);
	}
	void eval(int i,int l,int r)
	{
		if(lazyflag[i])
		{
			dat[i]=updatefn(dat[i],lazy[i],l,r);
			if(r-l>1)
			{
				lazy[2*i+1]=lazycalcfn(lazy[2*i+1],lazy[i]);
				lazy[2*i+2]=lazycalcfn(lazy[2*i+2],lazy[i]);
				lazyflag[2*i+1]=lazyflag[2*i+2]=true;
			}
			lazy[i]=lazydefvalue;
			lazyflag[i]=false;
		}
	}
	void update(int a,int b,T x,int k=0,int l=0,int r=-1)//[a,b)
	{
		if(r<0)r=n;
		eval(k,l,r);
		if(b<=l||r<=a)return;
		else if(a<=l&&r<=b)
		{
			lazy[k]=lazycalcfn(lazy[k],x);
			lazyflag[k]=true;
			eval(k,l,r);
		}
		else
		{
			update(a,b,x,2*k+1,l,(l+r)/2);
			update(a,b,x,2*k+2,(l+r)/2,r);
			dat[k]=calcfn(dat[2*k+1],dat[2*k+2]);
		}
	}
	T query(int a,int b,int k=0,int l=0,int r=-1)//[a,b)
	{
		if(r<0)r=n;
		eval(k,l,r);
		if(b<=l||r<=a)return defvalue;
		else if(a<=l&&r<=b)return dat[k];
		else return calcfn(
			query(a,b,2*k+1,l,(l+r)/2),
			query(a,b,2*k+2,(l+r)/2,r)
		);
	}
};
int N,K,M;
int A[3030];
long dp[3030][3030];
main()
{
	cin>>N>>K>>M;
	for(int i=0;i<N;i++)cin>>A[i];
	for(int i=1;i<=N;i++)dp[0][i]=-1e18;
	for(int i=0;i<K;i++)
	{
		vector<long>init(N+1);
		for(int j=0;j<=N;j++)
		{
			init[j]=dp[i][j];
			dp[i+1][j]=-1e18;
		}
		{
			lazysegtree<long>P(N+1,(long)-1e18,
				[](long a,long b){return a<b?b:a;},
				[](long a,long b){return a+b;},
				[](long a,long b,int l,int r){return a+b;});
			P.copy(init);
			for(int j=1;j<=N;j++)
			{
				P.update(j-M,j,A[j-1]);
				dp[i+1][j]=max(dp[i+1][j],P.query(j-M,j));
			}
		}
		{
			lazysegtree<long>P(N+1,(long)-1e18,
				[](long a,long b){return a<b?b:a;},
				[](long a,long b){return a+b;},
				[](long a,long b,int l,int r){return a+b;});
			P.copy(init);
			for(int j=1;j<=N;j++)
			{
				P.update(j-M,j,-A[j-1]);
				dp[i+1][j]=max(dp[i+1][j],P.query(j-M,j));
			}
		}
	}
	cout<<dp[K][N]<<endl;
}