d[3010*4];
w[3010];
inline max(a,b){return a>b?a:b;}
main(i,k,n,m){
	scanf("%d%d",&n,&m);
	for(i=0;i<n;++i)scanf("%d",w+i);
	for(k=n*4+3;k>=0;--k)d[k]=-999999;
	d[0]=d[7]=0;
	for(i=0;i<n-1;++i)for(k=max(m,i+3)*4;k-=2;)
		d[k+2]=max(d[k+2],d[k+3]),
		d[k+3]=max(d[k-2],d[k-1]+w[i]);
	printf("%d",max(max(d[m*4+0],d[m*4+1]),max(d[m*4+2],d[m*4+3]+w[n-1])));
	return 0;
}