#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll=long long;
int inf=1000000000;
using mint=modint1000000007;



vector<int> grundy(101,-1);
int g(int i){
    if(grundy[i]!=-1)return grundy[i];
    int a=-1,b=-1;
    if(i>=3){
        if(i%3==0||i%3==2)a=g(i/3);
        else if(i%3==1)a=g(i/3+1);
        
    }
    if(i>=2){
        if(i&1)b=g(i/2)^g(i/2+1);
        else b=0;
    }

    if(a!=0&&b!=0)return grundy[i]=0;
    else if(a!=1&&b!=1)return grundy[i]=1;
    else return grundy[i]=2;
}
int main()
{
    int n;
    cin>>n;

    if(g(n))cout<<"A"<<endl;
    else cout<<"B"<<endl;
    
}