#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int f[10020][1000],a[20000],n,m;
int main()
{
  scanf("%d%d",&n,&m);
  for (int i=1;i<=n;i++) scanf("%d",&a[i]);
  for (int i=1;i<=n;i++)
  {
   f[i][0]=f[i-1][0];
   for (int j=1;j<=m;j++)
   {
     if (j<=i) f[i][0]=max(f[i][0],f[i-j][j]);
     f[i][j]=max(f[i][j],f[i-1][j-1]+a[i]);
   }
  }
  printf("%d\n",f[n][0]);
  return 0;
}