#include<cstdio>

 #include<iostream>

 #include<cmath>

 #include<algorithm>

 #include<cstring>

 #include<cstdlib>

 #include<cctype>

 #include<vector>

 #include<stack>

 #include<queue>

 using namespace std;

 #define enter puts("")

 #define space putchar(' ')

 #define Mem(a) memset(a, 0, sizeof(a))

 typedef long long ll;

 typedef double db;

 const int INF = 0x3f3f3f3f;

 const int eps = 1e-;

 const int maxn = 1e4 + ;

 inline ll read()

 {

     ll ans = ;

     char ch = getchar(), last = ' ';

     while(!isdigit(ch)) {last = ch; ch = getchar();}

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

     if(last == '-') ans = -ans;

     return ans;

 }

 inline void write(ll x)

 {

     if(x < ) x = -x, putchar('-');

     if(x >= ) write(x / );

     putchar(x %  + '');

 }

 int n, m, a[maxn];

 int dp[maxn][maxn];

 int main()

 {

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

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

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

     {

         dp[i][] = dp[i - ][];

         for(int j = ; j <= min(i, m); ++j) dp[i][] = max(dp[i][], dp[i - j][j]);

         for(int j = ; j <= min(i, m); ++j) dp[i][j] = max(dp[i][j], dp[i - ][j - ] + a[i]);

     }

     write(dp[n][]); enter;

     return ;

 }