#include <bits/stdc++.h>
using namespace std;
long long n, k, x;
long long m[200010];
long long answer;
struct node {
  long long pre;
  long long next;
} p[200010];
int main() {
  long long a;
  while (~scanf("%I64d %I64d %I64d", &n, &k, &x)) {
    answer = p[1].pre = p[n].next = 0;
    a = x;
    for (long long i = k - 1; i > 0; i--) a *= x;
    for (long long i = 1; i <= n; i++) {
      scanf("%d", &m[i]);
      p[i].pre = (m[i - 1] | p[i - 1].pre);
    }
    for (long long i = n; i >= 1; i--) {
      if (i < n) p[i].next = (p[i + 1].next | m[i + 1]);
      answer = max(answer, (p[i].pre | p[i].next | m[i] * a));
    }
    printf("%I64d\n", answer);
  }
  return 0;
}
