#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, x;
  const int Count = 200001;
  unsigned long long a[Count];
  unsigned long long pre[Count];
  unsigned long long nex[Count];
  while (cin >> n >> k >> x) {
    for (int i = 0; i < n; i++) cin >> a[i];
    int all = 0;
    for (int i = 0; i < n; i++) all = a[i] | all;
    unsigned long long max = a[0];
    int maxid = 0;
    pre[0] = 0;
    for (int i = 1; i < n; i++) {
      pre[i] = pre[i - 1] | a[i - 1];
      if (a[i] > max) {
        max = a[i];
        maxid = i;
      }
    }
    nex[n - 1] = 0;
    for (int i = n - 2; i >= 0; i--) nex[i] = nex[i + 1] | a[i + 1];
    unsigned long long xpowk = 1;
    for (int i = 0; i < k; i++) xpowk *= x;
    for (int i = 0; i < n; i++) {
      if ((pre[i] | nex[i] | (a[i] * xpowk)) > max)
        max = (pre[i] | nex[i] | (a[i] * xpowk));
    }
    cout << max << endl;
  }
  return 0;
}
