#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>

#define FORR(i,b,e) for(int i=(b);i<(int)(e);++i)
#define FOR(i,e) FORR(i,0,e)
#define sortuniq(v) sort(v.begin(), v.end()), v.erase(unique(v.begin(),v.end()),v.end())
#define dump(var) cerr << #var ": " << var << "\n"
#define dumpc(con) for(auto& e: con) cerr << e << " "; cerr<<"\n"

typedef long long ll;
typedef unsigned long long ull;

const double EPS = 1e-6;
const int d4[] = {0, -1, 0, 1, 0};

using namespace std;


int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    const int win1 = 3, win2 = 0;
    int N;
    cin >> N;
    vector<int> w(max(4, N+1));
    w[0] = w[1]= win2;
    w[2] = w[3] = win1;
    FORR(i, 4, N+1) {
        if ((2 ^ w[i/2] ^ w[i-i/2]) == 1 ||
            (2 ^ w[i/3] ^ w[(i-i/3)/2] ^ w[i-(i-i/3)/2]) == 1) {
            w[i] = win2;
        }
        else {
            w[i] = win1;
        }
    }
    cout << (w[N]? 'A': 'B') << '\n';

    return 0;
}