#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
#include <iostream>
#include <utility>
#include <set>
#include <cctype>
#include <queue>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cmath>

using namespace std;
typedef long long ll;

int grundy(int x) {
    set<int> s;
    if (x >= 3) {
        int a = x/3;
        int b = (x-a) / 2;
        int c = x-a-b;
        s.insert(grundy(a)^grundy(b)^grundy(c));
    }
    if (x >= 2) {
        int a = x/2;
        int b = x-a;
        s.insert(grundy(a)^grundy(b));
    }
    int g = 0;
    while (s.count(g)) g++;
    return g;
}

int main(void) {
    int N;
    cin >> N;
    int ans = grundy(N);
    if (ans == 0) cout << "B" << endl;
    else cout << "A" << endl;
    return 0;
}