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

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N; cin >> N;
    vector<int> G(N+2);
    G.at(1) = 0,G.at(2) = 1;
    for(int i=3; i<=N; i++){
        int S = 0;
        if(i%2) S |= 1<<(G.at(i/2)^G.at(i/2+1));
        else S |= 1; 
        if(i%3 == 0) S |= 1<<G.at(i/3);
        else if(i%3 == 1) S |= 1<<G.at(i/3+1);
        else S |= 1<<G.at(i/3);
        for(int k=0; ; k++) if(!(S&(1<<k))){G.at(i) = k; break;}
    }
    if(G.at(N)) cout << "A\n";
    else cout << "B\n";
}