#include <bits/stdc++.h>
using namespace std;
long long f[5005][5005];
long long sum[5005];
long long g[5005];
int n, m, k, x;
int main() {
  cin >> n >> k >> m;
  for (int i = 1; i <= n; i++) {
    scanf("%d", &x), sum[i] = sum[i - 1] + x;
  }
  for (int i = k; i <= n; i++) {
    f[1][i] = sum[i] - sum[i - k];
    g[i] = max(g[i - 1], f[1][i]);
  }
  for (int i = 2; i <= m; i++) {
    for (int j = k; j <= n; j++) {
      f[i][j] = g[j - k] + sum[j] - sum[j - k];
    }
    for (int j = 1; j <= n; j++) g[j] = max(g[j - 1], f[i][j]);
  }
  long long ans = 0;
  for (int i = k; i <= n; i++) ans = max(ans, f[m][i]);
  cout << ans << endl;
}
