#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, x, p = 1;
  cin >> n >> k >> x;
  vector<long long> a(n + 1), orstg(n + 1), ordrp(n + 1);
  for (int i = 0; i < n; i++) cin >> a[i];
  orstg[0] = a[0];
  for (int i = 1; i < n; i++) orstg[i] = orstg[i - 1] | a[i];
  ordrp[n - 1] = a[n - 1];
  for (int i = n - 2; i >= 0; i--) ordrp[i] = ordrp[i + 1] | a[i];
  while (k--) p *= x;
  if (n == 1) {
    cout << a[0] * p << "\n";
    return 0;
  }
  long long ans = max((a[0] * p) | ordrp[1], orstg[n - 2] | (a[n - 1] * p));
  for (int i = 1; i < n - 1; i++)
    ans = max(ans, orstg[i - 1] | ordrp[i + 1] | (a[i] * p));
  cout << ans << "\n";
  return 0;
}
