#include <bits/stdc++.h>
using namespace std;
const long long MOD = 998244353;
const long long N = 5e3 + 5;
long long a[N];
long long pre[N];
long long dp[N][N];
long long n, m, k;
long long check = 0;
long long go(long long pos, long long kk) {
  if (kk == k) return 0;
  if (pos == n + 1) return -1e15;
  long long &ans = dp[pos][kk];
  if (ans != -1) return ans;
  ans = go(pos + 1, kk);
  if (pos + m - 1 <= n) {
    ans = max(ans, pre[pos + m - 1] - pre[pos - 1] + go(pos + m, kk + 1));
  }
  return ans;
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> m >> k;
  for (long long i = 1; i <= n; i++) {
    cin >> a[i];
    pre[i] = pre[i - 1] + a[i];
  }
  memset(dp, -1, sizeof(dp));
  cout << go(1, 0) << endl;
}
