#include <bits/stdc++.h>
using namespace std;
const long double pi = 2 * acos(0.0);
template <class T>
bool umin(T& a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
bool umax(T& a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T, class TT>
bool pal(T a, TT n) {
  int k = 0;
  for (int i = 0; i <= n / 2; i++) {
    if (a[i] != a[n - i - 1]) {
      k = 1;
      break;
    }
  }
  return k ? 0 : 1;
}
long long a[222222];
long long dp[5005][5005];
int main() {
  memset(dp, -1, sizeof dp);
  int n, m, k;
  cin >> n >> m >> k;
  for (int i = 1; i <= n; i++) cin >> a[i], a[i] += a[i - 1];
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= k; j++) {
      dp[i][j] = dp[i - 1][j];
      if (j == 1) {
        if (i - m >= 0) dp[i][j] = max(a[i] - a[i - m], dp[i][j]);
      } else if (i - m > 0 && dp[i - m][j - 1] != -1)
        dp[i][j] = max(dp[i][j], dp[i - m][j - 1] + a[i] - a[i - m]);
    }
  }
  long long ans = 0;
  for (int i = 1; i <= n; i++) ans = max(ans, dp[i][k]);
  cout << ans;
  getchar();
  getchar();
  return 0;
}
