#include <iostream>

#include <cstdio>

#include <algorithm>

#include <cstdlib>

#include <cstring>

#include <cmath>

#include <vector>

#include <stack>

#define ll long long

#define inf (-1u>>1)

using namespace std;

inline int read()

{

    int ans=,f=;

    char ch=getchar();

    while(!isdigit(ch)){if(ch=='-')f=-f;ch=getchar();}

    while(isdigit(ch)){ans=*ans+ch-'';ch=getchar();}

    return ans*f;

}

int d[];

int f[][];

int main()

{

    int n,m;

    n=read();m=read();

    for(int i=;i<=n;i++)d[i]=read();

    for(int i=;i<=n;i++)

    {

        for(int j=;j<=m;j++)

        {

            if(j>)f[i][j]=max(f[i][j],f[i-][j-]+d[i]);

            if(i>=j)

            {

                f[i][]=max(f[i-j][j],f[i][]);

                f[i][]=max(f[i-][],f[i][]);

            }

        }

    }

    cout<<f[n][];

    return ;

}