// #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using pii = pair<int, int>;
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define repr(i, n) for (int i = (int)(n - 1); i >= 0; --i)

bool solve() {
    int x, y, K, p;
    cin >> x >> y >> K >> p;
    int r = x + y - K;
    if (r & 1) {
        if (x <= r / 2) {
            if (K & 1) {
                if (p == 1) return false;
            } else {
                if (p == -1) return false;
            }
        }
        if (y <= r / 2 && p == -1) return false;
        return true;
    } else {
        if (x <= r / 2) {
            if (K & 1) {
                if (p == -1) return true;
            } else {
                if (p == 1) return true;
            }
        }
        if (y <= r / 2 && p == 1) return true;
        return false;
    }
}
int main() {
    cout << (solve() ? "Alice" : "Bob") << '\n';
    return 0;
}