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

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n; 
    cin >> n;
    vector<int> memo(n+1, -1);
    auto g = [&] (auto self, int i) -> int {
        if (memo[i] != -1) return memo[i];
        if (i == 0 || i == 1) return memo[i] = 0;
        set<int> st;
        int res = 0;
        if (i % 3 == 1) {
            res = self(self, i/3 + 1);
        } else {
            res = self(self, i/3);
        }
        if (res == 0) return memo[i] = 1;
        res = 0;
        if (i & 1) {
            res = i^(i-1);
        } else {
            res = 0;
        }
        return memo[i] = res;
    };
    cout << (g(g, n) == 0 ? "B": "A") << "\n";
}