#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 1000000007;
// constexpr int MOD = 998244353;
constexpr int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
constexpr int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  int n; cin >> n;
  vector<int> a(n);
  REP(i, n) {
    cin >> a[i];
    chmin(a[i], 2);
  }
  vector dp(n, vector(3, -1));
  dp[0][a[0]] = 1;
  FOR(i, 1, n) {
    dp[i][1] = dp[i - 1][a[i - 1]] ^ 1;
    if (a[i] == 2) dp[i][2] = (dp[i][1] == 0 || dp[i - 1][a[i - 1]] == 0 ? 1 : 0);
  }
  cout << (dp[n - 1][a[n - 1]] == 1 ? "Alice\n" : "Bob\n");
  return 0;
}