#include <bits/stdc++.h>
using namespace std;
inline int readInt() {
  int sign = 1, x = 0, c = getc(stdin);
  while (c <= 32) {
    c = getc(stdin);
  }
  if (c == '-') {
    sign = -1;
    c = getc(stdin);
  }
  while ('0' <= c && c <= '9' && c != EOF) {
    x = (x << 1) + (x << 3) + c - '0';
    c = getc(stdin);
  }
  return x * sign;
}
inline void writeLong(long long x) {
  if (x < 0) {
    putc('-', stdout);
    x = -x;
  }
  char s[40];
  int n = 0;
  while (x || !n) {
    s[n++] = '0' + x % 10;
    x /= 10;
  }
  while (n--) {
    putc(s[n], stdout);
  }
}
bool des(int i, int j) { return i > j; }
bool asc(int i, int j) { return i < j; }
const int M = 200003;
int a[M], suf[M], pre[M];
int main(int argc, char const *argv[]) {
  int n = readInt(), k = readInt(), x = readInt();
  for (int i = 1; i <= n; ++i) a[i] = readInt();
  unsigned long long pow = 1;
  while (k--) pow *= x;
  unsigned long long ans = 0, res = 0;
  for (int i = 1; i <= n; ++i) pre[i] = a[i - 1] | pre[i - 1];
  for (int j = n; j > 0; --j) suf[j] = a[j + 1] | suf[j + 1];
  for (int i = 1; i <= n; ++i) ans = max(ans, pre[i] | a[i] * pow | suf[i]);
  writeLong(ans);
  putchar('\n');
  return 0;
}
