#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
const int eps = -1e6;
const int MAX = 200010;
long long int n, k, x;
long long int a[MAX], pre[MAX], s[MAX];
long long int expo(long long int a, long long int b) {
  long long int x = 1, y = a;
  while (b > 0) {
    if (b & 1) x = (x * y);
    y = (y * y);
    b >>= 1;
  }
  return x;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin >> n >> k >> x;
  for (int i = 0, _n = (n); i < _n; ++i) {
    cin >> a[i];
    if (i == 0)
      pre[i] = a[i];
    else
      pre[i] = pre[i - 1] | a[i];
  }
  for (int i = n - 1; i >= 0; i--) {
    if (i == n - 1)
      s[i] = a[i];
    else
      s[i] = s[i + 1] | a[i];
  }
  long long int tmp = expo(x, k);
  long long int res = 0;
  for (int i = 0, _n = (n); i < _n; ++i) {
    long long int z = a[i] * 1ll * tmp;
    if (i == 0)
      res = max(res, z | s[1]);
    else if (i == n - 1)
      res = max(res, pre[n - 2] | z);
    else
      res = max(res, pre[i - 1] | z | s[i + 1]);
  }
  cout << res << endl;
  return 0;
}
