#include <iostream>
#include <set>
using namespace std;

int g[110];

int main() {
    int N;
    cin >> N;

    g[2] = 1;
    for (int x = 3; x <= N; x++) {
        set<int> s;
        if (x % 2 == 0) s.insert(g[x / 2] ^ g[x / 2]);
        else s.insert(g[x / 2] ^ g[x / 2 + 1]);

        if (x % 3 == 0) s.insert(g[x / 3] ^ g[x / 3] ^ g[x ^ 3]);
        else if (x % 3 == 1) s.insert(g[x / 3] ^ g[x / 3] ^ g[x / 3 + 1]);
        else s.insert(g[x / 3] ^ g[x / 3 + 1] ^ g[x / 3 + 1]);

        int num = 0;
        for (int n : s) {
            if (num != n) break;
            num++;
        }
        g[x] = num;
    }

    if (g[N]) cout << "A" << endl;
    else cout << "B" << endl;
    
    return 0;
}