#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
const double PI = acos(-1.0);
const double E = exp(1.0);
const int M = 200010;
long long a[M];
long long ans[M][2];
int main() {
  int n, k, x;
  cin >> n >> k >> x;
  long long temp = 1;
  while (k--) temp *= x;
  for (int i = 1; i <= n; ++i) {
    scanf("%d", &a[i]);
    ans[i][0] = (ans[i - 1][0] | a[i]);
  }
  long long mx = 0;
  for (int i = n; i > 0; --i) {
    mx = max(mx, ans[i + 1][1] | ans[i - 1][0] | (a[i] * temp));
    ans[i][1] = ans[i + 1][1] | a[i];
  }
  cout << mx << endl;
  return 0;
}
