#include <bits/stdc++.h>
using namespace std;
const long long OO = 1LL << 60;
const long double dOO = (double)INT_MAX;
long long mod = 1000000007;
long double eps = 1e-6;
long long dp[5005][5005];
long long a[5005];
long long sum[5005];
long long m, n;
long long calc(int p, int rem) {
  if (p - 1 + rem * m >= n) return -100000000;
  if (rem == 0) return 0;
  long long& ret = dp[p][rem];
  if (ret != -1) return ret;
  ret = max(sum[p + m - 1] - (p ? sum[p - 1] : 0) + calc(p + m, rem - 1),
            calc(p + 1, rem));
  return ret;
}
int main() {
  long long k;
  scanf("%I64d %I64d %I64d", &n, &m, &k);
  for (int i = 0; i < n; i++) scanf("%I64d", a + i);
  partial_sum(a, a + n, sum);
  memset(dp, -1, sizeof dp);
  long long ans = calc(0, k);
  printf("%I64d\n", ans);
}
