#include <bits/stdc++.h>
using namespace std;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    long long x, y, k, p, t;
    cin >> x >> y >> k >> p;
    t = x + y - k;
    long long at = (t + 1) / 2, bt = t / 2;
    if(t & 1){
        if(min(x, y) >= max(at, bt)){
            cout << "Alice" << '\n';
            return 0;
        }
        if(y <= bt && p == -1){
            cout << "Bob" << '\n';
            return 0;
        }
        if(x <= bt && ((k % 2 == 1) ^ (p == -1))){
            cout << "Bob" << '\n';
            return 0;
        }
        cout << "Alice" << '\n';
    }else{
        if(min(x, y) >= max(at, bt)){
            cout << "Bob" << '\n';
            return 0;
        }
        if(y <= at && p == 1){
            cout << "Alice" << '\n';
            return 0;
        }
        if(x <= at && ((k % 2 == 1) == (p == -1))){
            cout << "Alice" << '\n';
            return 0;
        }
        cout << "Bob" << '\n';
    }
}