#include <bits/stdc++.h>
using namespace std;
long long n, k, x;
long long mult = 1;
long long a[200005];
long long b[200005];
long long r;
long long pd[200005][2];
long long go(int curr, int fez) {
  long long L = 0, R = 0;
  if (curr == n) return 0;
  if (pd[curr][fez] != -1) return pd[curr][fez];
  if (!fez) R = go(curr + 1, 1) | (a[curr] * mult) | b[curr];
  L = go(curr + 1, fez) | a[curr];
  return pd[curr][fez] = max(L, R);
}
int main(void) {
  cin >> n >> k >> x;
  for (int i = 0; i < k; i++) {
    mult *= x;
  }
  memset(pd, -1, sizeof(pd));
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  b[0] = 0;
  for (int i = 1; i <= n; i++) {
    b[i] = b[i - 1] | a[i - 1];
  }
  cout << go(0, 0) << endl;
  return 0;
}
