#include <bits/stdc++.h>
using namespace std;
long long temp;
int main() {
  long long n, k, x;
  long long a[200005];
  cin >> n >> k >> x;
  long long i;
  for (i = 0; i < n; ++i) cin >> a[i];
  long long preOr[200005], sufOr[200005];
  long long xPower[15];
  xPower[0] = 1;
  for (i = 1; i <= k; ++i) xPower[i] = xPower[i - 1] * x;
  preOr[0] = a[0];
  for (i = 1; i < n; ++i) preOr[i] = preOr[i - 1] | a[i];
  sufOr[n - 1] = a[n - 1];
  for (i = n - 2; i >= 0; --i) sufOr[i] = sufOr[i + 1] | a[i];
  long long ans;
  long long maxAns = 0;
  for (i = 0; i < n; ++i) {
    long long before, after;
    if (i > 0)
      before = preOr[i - 1];
    else
      before = 0;
    if (i < n - 1)
      after = sufOr[i + 1];
    else
      after = 0;
    long long cur = a[i] * xPower[k];
    ans = before | cur | after;
    if (maxAns < ans) maxAns = ans;
  }
  cout << maxAns;
}
