#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
#define fix(x) fixed << setprecision(x)
#define asc(x) x, vector<x>, greater<x>
#define rep(i, n) for(ll i = 0; i < n; i++)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int x,y,k,p;
    bool ans;
    cin >> x >> y >> k >> p;
    if(p<0 && y<=(x+y-k)/2) ans = false;
    else if(p<0 && x<=(x+y-k+1)/2 && (k&1)) ans = true;
    else if(p<0 && x<=(x+y-k)/2 && !(k&1)) ans = false;
    else if(p>0 && y<=(x+y-k+1)/2) ans = true;
    else if(p>0 && x<=(x+y-k)/2 && (k&1)) ans = false;
    else if(p>0 && x<=(x+y-k+1)/2 && !(k&1)) ans = true;
    else ans = (x+y-k) & 1;
    cout << (ans?"Alice\n":"Bob\n");
    return 0;
}