#include <bits/stdc++.h>
using namespace std;
long long factorial(long long n) {
  if (n == 0) return 1;
  return (n * factorial(n - 1)) % 1000000007;
}
long long power(long long x, long long y) {
  if (y == 0)
    return 1;
  else if (y % 2 == 0)
    return (power(x, y / 2) * power(x, y / 2));
  else
    return (x * ((power(x, y / 2) * power(x, y / 2))));
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int tt = 1;
  while (tt--) {
    long long n, k, x;
    cin >> n >> k >> x;
    long long l[n];
    long long prefix[n];
    long long suffix[n];
    long long maxAns = 0;
    for (int i = 0; i < n; i++) {
      cin >> l[i];
    }
    if (n == 1) {
      cout << l[0] * power(x, k) << endl;
      return 0;
    }
    prefix[0] = l[0];
    for (int i = 1; i < n; i++) {
      prefix[i] = prefix[i - 1] | l[i];
    }
    suffix[n - 1] = l[n - 1];
    for (int i = n - 2; i >= 0; i--) {
      suffix[i] = suffix[i + 1] | l[i];
    }
    for (int i = 0; i < n; i++) {
      if (i == 0) {
        maxAns = max(maxAns, (l[i] * power(x, k)) | suffix[i + 1]);
        continue;
      }
      if (i == n - 1) {
        maxAns = max(maxAns, (l[i] * power(x, k)) | prefix[i - 1]);
        continue;
      } else {
        maxAns =
            max(maxAns, (l[i] * power(x, k)) | suffix[i + 1] | prefix[i - 1]);
      }
    }
    cout << maxAns << endl;
  }
}
