#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
// constexpr int MOD = 1000000007;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  constexpr int B = 47;
  int n, m; ll l; cin >> n >> m >> l;
  vector<int> a(n); REP(i, n) cin >> a[i];
  vector dp1(B, vector(n, 0));
  vector dp2(B, vector(n, 0LL));
  REP(i, n) {
    dp1[0][i] = (i + l) % n;
    dp2[0][i] = a[i];
  }
  REP(bit, B - 1) REP(i, n) {
    dp1[bit + 1][i] = dp1[bit][dp1[bit][i]];
    dp2[bit + 1][i] = dp2[bit][i] + dp2[bit][dp1[bit][i]];
  }
  const ll x = ll{n} * m % l;
  ll ans = -LINF;
  for (int i = 0; i < x && i < n; ++i) {
    ll t = ll{n} * m / l + 1, sum = 0;
    for (int bit = 0, pos = i % n; t > 0; ++bit, t >>= 1) {
      if (t & 1) {
        sum += dp2[bit][pos];
        pos = dp1[bit][pos];
      }
    }
    chmax(ans, sum);
  }
  for (ll i = max(x, l - n); i < l; ++i) {
    ll t = ll{n} * m / l, sum = 0;
    for (int bit = 0, pos = i % n; t > 0; ++bit, t >>= 1) {
      if (t & 1) {
        sum += dp2[bit][pos];
        pos = dp1[bit][pos];
      }
    }
    chmax(ans, sum);
  }
  cout << ans << '\n';
  return 0;
}