#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <atcoder/modint>

using namespace std;
using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;
#define rep(i,n) for(int i=0; i<(int)(n); i++)

const i64 INF = 1001001001001001001;
using Modint = atcoder::static_modint<998244353>;

bool solve2(i64 x, i64 y, i64 k, i64 p){
    // (x+y-k) % 2 == 0
    if(x-y >= k) return p == -1;
    if(y-x >= k){
        if(k % 2 == 0) return p == -1;
        return p == 1;
    }
    return false;
}

bool solve(i64 x, i64 y, i64 k, i64 p){
    if((x+y-k)%2 == 1){
        bool q1 = !solve2(x-1, y, k, p);
        bool q2 = !solve2(x, y-1, k, p);
        return q1 || q2;
    }
    // (x+y-k) % 2 == 0
    if(x-y >= k) return p == 1;
    if(y-x >= k){
        if(k % 2 == 0) return p == 1;
        return p == -1;
    }
    return false;
}

int main(){
    i64 X, Y, K, P; cin >> X >> Y >> K >> P;
    bool ans = solve(X,Y,K,P);
    cout << (ans ? "Alice" : "Bob") << '\n';
    return 0;
}


struct ios_do_not_sync{
    ios_do_not_sync(){
        std::ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
    }
} ios_do_not_sync_instance;