#include <bits/stdc++.h>
using namespace std;
inline int getint() {
  static char c;
  while ((c = getchar()) < '0' || c > '9')
    ;
  int res = c - '0';
  while ((c = getchar()) >= '0' && c <= '9') res = res * 10 + c - '0';
  return res;
}
inline void relax(long long &a, const long long &b) {
  if (b > a) a = b;
}
const int MaxN = 200005;
int n, k, x;
long long res = 0, a[MaxN];
long long pref[MaxN];
long long suff[MaxN];
int main() {
  n = getint(), k = getint(), x = getint();
  for (int i = 1; i <= n; ++i) a[i] = getint();
  long long m = 1;
  while (k--) m *= x;
  for (int i = 1; i <= n; ++i) pref[i] = pref[i - 1] | a[i];
  for (int i = n; i >= 1; --i) suff[i] = suff[i + 1] | a[i];
  for (int i = 1; i <= n; ++i) {
    long long w = pref[i - 1] | a[i] * m | suff[i + 1];
    relax(res, w);
  }
  cout << res;
  return 0;
}
