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

int dfs(vector<int> &g, int N) {
    if (g[N] != -1) return g[N];

    int a = 0;
    if (N % 2 == 1) {
        a ^= dfs(g, N/2);
        a ^= dfs(g, N/2+1);
    }
    int b = 0;
    if (N % 3 != 1) {
        b ^= dfs(g, N/3);
    } else {
        b ^= dfs(g, N/3+1);
    }

    for (int i = 0; i < 3; i++) {
        if (a == i || b == i) continue;
        g[N] = i;
        break;
    }

    return g[N];
}

int main() {
    int N;
    cin >> N;
    vector<int> grundy(N+1, -1);
    grundy[1] = 0; grundy[2] = 1;
    dfs(grundy, N);

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