#include <bits/stdc++.h>
using namespace std;
int Set(int N, int pos) { return N = N | (1 << pos); }
int reset(int N, int pos) { return N = N & ~(1 << pos); }
bool check(int N, int pos) { return (bool)(N & (1 << pos)); }
int cas = 1;
int dxx[] = {-1, -1, -1, 0, 0, 1, 1, 1};
int dyy[] = {-1, 0, 1, -1, 1, -1, 0, 1};
int dx[] = {-1, 0, 0, 1};
int dy[] = {0, -1, 1, 0};
long long ans, i, j, l, n, k, x, y, ai[200006], bi[200006], ci[200006];
int main() {
  scanf("%lld%lld%lld", &n, &k, &x);
  for (i = 0; i < n; i++) scanf("%lld", &ai[i]);
  y = 1;
  for (i = 0; i < k; i++) y *= x;
  ans = 0;
  bi[0] = 0;
  for (i = 0; i < n; i++) {
    bi[i + 1] = bi[i] | ai[i];
  }
  ci[n] = 0;
  for (i = n; i >= 0; i--) {
    ci[i - 1] = ci[i] | ai[i - 1];
  }
  ans = 0;
  for (i = 0; i < n; i++) {
    ans = max(ans, bi[i] | ci[i + 1] | ai[i] * y);
  }
  printf("%lld\n", ans);
}
