#include <bits/stdc++.h>
using namespace std;
using Int = long long;
template <typename T1, typename T2>
inline void chmin(T1 &a, T2 b) {
  if (a > b) a = b;
}
template <typename T1, typename T2>
inline void chmax(T1 &a, T2 b) {
  if (a < b) a = b;
}
struct FastIO {
  FastIO() {
    cin.tie(0);
    ios::sync_with_stdio(0);
  }
} fastio_beet;
template <typename T>
void drop(const T &x) {
  cout << x << endl;
  exit(0);
}
signed main() {
  Int n, k, x;
  cin >> n >> k >> x;
  vector<Int> as(n);
  for (Int i = 0; i < n; i++) cin >> as[i];
  Int po = 1;
  for (Int j = 0; j < k; j++) po *= x;
  vector<Int> dp(n + 1, 0), pd(n + 1, 0);
  for (Int i = 0; i < n; i++) dp[i + 1] = dp[i] | as[i];
  for (Int i = n - 1; i > 0; i--) pd[i - 1] = pd[i] | as[i];
  Int ans = 0;
  for (Int i = 0; i < n; i++) chmax(ans, dp[i] | pd[i] | (as[i] * po));
  cout << ans << endl;
  return 0;
}
