3661

/*
动归，自己开始没搞清楚，怎样来表达只有当休息为0的时候才继续跑步或者休息
如果休息的话，不参与计算任务。
*/

// include file
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cctype>
#include <ctime>

#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <bitset>
#include <strstream>

#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <set>
#include <list>
#include <functional>

using namespace std;

// typedef
typedef long long LL;
typedef unsigned long long ULL;

// 
#define read freopen("in.txt","r",stdin)
#define write freopen("out.txt","w",stdout)
#define FORi(a,b,c) for(int i=(a);i<(b);i+=c)
#define FORj(a,b,c) for(int j=(a);j<(b);j+=c)
#define FORk(a,b,c) for(int k=(a);k<(b);k+=c)
#define FORp(a,b,c) for(int p=(a);p<(b);p+=c)

#define FF(i,a)    for(int i=0;i<(a);i+++)
#define FFD(i,a)   for(int i=(a)-1;i>=0;i--)
#define Z(a) (a<<1)
#define Y(a) (a>>1)

const double eps = 1e-6;
const double INFf = 1e10;
const int INFi = 1000000000;
const double Pi = acos(-1.0);

template<class T> inline T sqr(T a){return a*a;}
template<class T> inline T TMAX(T x,T y)
{
	if(x>y) return x;
	return y;
}
template<class T> inline T TMIN(T x,T y)
{
	if(x<y) return x;
	return y;
}
template<class T> inline void SWAP(T &x,T &y)
{
	T t = x;
	x = y;
	y = t;
}
template<class T> inline T MMAX(T x,T y,T z)
{
	return TMAX(TMAX(x,y),z);
}


// code begin
// dp[i][j] 表示i分钟时，疲劳度为j的最大距离
int DP[10010];
int Lei[510];
int a,N,M;
int main()
{
	read;
	write;
	while(scanf("%d %d",&N,&M)!=-1)
	{
		memset(Lei,0,sizeof(Lei));
		memset(DP,0,sizeof(DP));
		FORi(1,N+1,1)
		{
			scanf("%d",&a);
			if(DP[i-1]>DP[i]) DP[i] = DP[i-1];
			for(int j=M;j>=1;j--)
			{
				Lei[j] = Lei[j-1]+a;
			}
			Lei[0] = DP[i];
			for(int j=1;j<=M;j++)
			{
				if(i+j>N) break;
				if(DP[i+j]<Lei[j])
					 DP[i+j]=Lei[j];
			}
		}
		printf("%d\n",DP[N]);
	}
	return 0;
}