#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
//#include <boost/multiprecision/cpp_ll.hpp>
//typedef boost::multiprecision::cpp_ll ll;
typedef long double dd;
#define i_7 (ll)(1E9+7)
//#define i_7 998244353
#define i_5 i_7-2
ll mod(ll a){
    ll c=a%i_7;
    if(c>=0)return c;
    return c+i_7;
}
typedef pair<ll,ll> l_l;
ll inf=(ll)1E16;
#define rep(i,l,r) for(ll i=l;i<=r;i++)
#define pb push_back
ll max(ll a,ll b){if(a<b)return b;else return a;}
ll min(ll a,ll b){if(a>b)return b;else return a;}
void Max(ll &pos,ll val){pos=max(pos,val);}//Max(dp[n],dp[n-1]);
void Min(ll &pos,ll val){pos=min(pos,val);}
void Add(ll &pos,ll val){pos=mod(pos+val);}
dd EPS=1E-9;
#define endl "\n"
#define fastio ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);

ll g[1000];
ll hoge(ll x){
    if(x==1)return 0;
    bool b[1000];rep(i,0,999)b[i]=false;
    if(x>=2){
        if(x%2==0){
            b[hoge(x/2)^hoge(x/2)]=1;
        }else{
            b[hoge((x+1)/2)^hoge((x-1)/2)]=1;
        }
    }
    if(x>=3){
        if(x%3==0){
            b[hoge(x/3)^hoge(x/3)^hoge(x/3)]=1;
        }else if(x%3==1){
            b[hoge((x-1)/3)^hoge((x-1)/3)^hoge((x-1)/3+1)]=1;
        }else{
            b[hoge((x-2)/3)^hoge((x-2)/3+1)^hoge((x-2)/3+1)]=1;
        }
    }
    rep(i,0,999){
        if(!b[i]){
            return g[x]=i;
        }
    }
    return 1;
}
int main(){fastio
    ll n;cin>>n;
    if(hoge(n)==0){
        cout<<"B"<<endl;
    }else{
        cout<<"A"<<endl;
    }
    
    return 0;
}