#include <bits/stdc++.h>
using namespace std;
int n, k;
unsigned long long x;
const int MX = 200 * 1000 + 9;
unsigned long a[MX];
int cnt_bits[32];
void add_to_cnt(unsigned long A, int delta) {
  for (int i = 0; i < 32; i++) {
    cnt_bits[i] += (A & 1) * delta;
    A >>= 1;
  }
}
unsigned long get_OR() {
  unsigned long res = 0UL;
  for (int i = 0; i < 32; i++)
    if (cnt_bits[i] > 0) res |= (1UL << i);
  return res;
}
int main() {
  cin >> n >> k >> x;
  unsigned long long x_pow_k = 1LL;
  for (int i = 0; i < k; i++) x_pow_k *= x;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    add_to_cnt(a[i], +1);
  }
  unsigned long long best = 0ULL;
  for (int i = 0; i < n; i++) {
    add_to_cnt(a[i], -1);
    unsigned long have = get_OR();
    unsigned long long will_get = have | (a[i] * x_pow_k);
    best = max(best, will_get);
    add_to_cnt(a[i], +1);
  }
  cout << best;
  return 0;
}
