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

int memo[110];

int f(int n) {
    if (memo[n] != -1)
        return memo[n];
    if (n == 1)
        return 0;

    int used[5] = {};

    if (n >= 2) {
        int tmp = f(n / 2) ^ f(n - n / 2);
        used[tmp] = 1;
    }
    if (n >= 3) {
        int a = n / 3;
        int b = (n - a) / 2;
        int c = n - a - b;
        int tmp = f(a) ^ f(b) ^ f(c);
        used[tmp] = 1;
    }

    for (int i = 0; i < 3; i++) {
        if (!used[i])
            return memo[n] = i;
    }
}

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

    for (int i = 0; i <= N; i++) {
        memo[i] = -1;
    }

    cout << (f(N) ? 'A' : 'B') << endl;
}