#include <bits/stdc++.h>
using namespace std;
const long long MAXN = 1000005;
long long pw(long long b, long long r, long long md) {
  long long ans = 1;
  while (r) {
    if (r & 1) ans = (ans * b) % md;
    b = (b * b) % md;
    r >>= 1;
  }
  return ans;
}
bool cmp(pair<long long, long long> a, pair<long long, long long> b) {
  if (a.first == b.first) return a.second < b.second;
  return a.first > b.first;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long n, m, k;
  cin >> n >> m >> k;
  long long dp[n][k + 1];
  for (long long i = 0; i <= n - 1; ++i)
    for (long long j = 0; j <= k; ++j) dp[i][j] = -1e18;
  long long arr[n];
  for (long long i = 0; i <= n - 1; ++i) cin >> arr[i];
  long long pref[n];
  pref[0] = arr[0];
  for (long long i = 1; i <= n - 1; ++i) pref[i] = pref[i - 1] + arr[i];
  for (long long i = 0; i <= n - 1; ++i) dp[i][0] = 0;
  dp[m - 1][1] = pref[m - 1];
  long long ans = 0;
  for (long long i = m; i <= n - 1; ++i) {
    for (long long j = 0; j <= k; ++j) {
      dp[i][j] = dp[i - 1][j];
      if (j == 0) continue;
      dp[i][j] = max(dp[i][j], dp[i - m][j - 1] + pref[i] - pref[i - m]);
    }
  }
  for (long long i = 0; i <= n - 1; ++i) ans = max(ans, dp[i][k]);
  cout << ans << '\n';
  return 0;
}
