#include <bits/stdc++.h>
using namespace std;
unsigned long long a[1000111], b[1000011], forw[1000111];
int main() {
  int i, n, k, loc = -1;
  unsigned long long mx = 0LLU, x;
  scanf("%d %d %llu", &n, &k, &x);
  for (i = 0; i < n; i++) scanf("%llu", &a[i]);
  forw[0] = a[0];
  for (i = 1; i < n; i++) forw[i] = forw[i - 1] | a[i];
  b[n - 1] = a[n - 1];
  for (i = n - 2; i >= 0; i--) b[i] = b[i + 1] | a[i];
  b[n] = 0;
  unsigned long long ans;
  unsigned long long t = a[0];
  for (i = 0; i < k; i++) t = t * x;
  ans = t | b[1];
  for (i = 0; i < n; i++) {
    unsigned long long t = a[i];
    for (int j = 0; j < k; j++) t = t * x;
    unsigned long long y = forw[i - 1] | t;
    y = y | b[i + 1];
    ans = max(ans, y);
  }
  printf("%llu\n", ans);
  return 0;
}
