#include<iostream>
#include<cstring>
using namespace std;
const int BUF = 105;


int N;

void read() {
    cin >> N;
}


int rec(int n, int dp[BUF]) {
    if (n == 0) return 1;
    if (n == 1) return 0;
    
    int &ret = dp[n];
    if (ret != -1) return ret;
    
    bool S[BUF] = {};
    S[rec(n / 2, dp) ^ rec((n + 1) / 2, dp)] = true;
    if (n >= 3)
        S[rec(n / 3, dp) ^ rec((n + 1) / 3, dp) ^ rec((n + 2) / 3, dp)] = true;
    
    for (int i = 0; i < BUF; ++i)
        if (!S[i])
            return ret = i;
}


void work() {
    int dp[BUF];
    memset(dp, - 1, sizeof(dp));

    cout << (rec(N, dp) == 0 ? 'B' : 'A') << endl;
}


int main() {
    read();
    work();
    return 0;
}