#include <bits/stdc++.h>
using namespace std;
int main(){
  int N, K;
  cin >> N >> K;
  vector<int> A(N);
  for (int i = 0; i < N; i++){
    cin >> A[i];
  }
  vector<long long> dp(N + 1, 0);
  for (int i = 0; i < N; i++){
    for (int j = max(i - K + 1, 0); j <= i; j++){
      dp[i + 1] = max(dp[i + 1], dp[j]);
    }
    for (int j = max(i - K + 2, 0); j <= i; j++){
      dp[j] = dp[j] + A[i];
    }
  }
  long long ans = 0;
  for (int i = 0; i <= N; i++){
    ans = max(ans, dp[i]);
  }
  cout << ans << endl;
}