#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9, mod = 1e9 + 7, N = 1e5 + 9;
long long n, k, x, ans = 0, a[200000], f[200000];
long long pw(long long a, long long b) {
  int res = 1;
  for (int i = 1; i < b + 1; i++) res *= a;
  return res;
}
long long L[200000], R[200000];
int main() {
  ios::sync_with_stdio(false);
  cin >> n >> k >> x;
  long long T = pw(x, k), ans = 0;
  for (int i = 0; i < n; i++) cin >> a[i];
  L[0] = a[0];
  for (int i = 1; i < n; i++) L[i] = L[i - 1] | a[i];
  R[n - 1] = a[n - 1];
  for (int i = n - 2; i >= 0; i--) R[i] = R[i + 1] | a[i];
  ans = max(L[n - 2] | (a[n - 1] * T), (R[1] | (a[0] * T)));
  for (int i = 1; i < n - 1; i++) {
    ans = max(ans, (L[i - 1] | (a[i] * T) | R[i + 1]));
  }
  cout << ans << "\n";
}
