#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
#define rep(i, n) REP(i, 0, n)
#define REP(i, s, e) for (ll i = (s); i < (ll)(e); i++)
#define repr(i, n) REPR(i, n, 0)
#define REPR(i, s, e) for (ll i = (ll)(s - 1); i >= (ll)(e); i--)
#define all(r) r.begin(), r.end()
#define rall(r) r.rbegin(), r.rend()

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;

template <typename T, typename U>
bool chmax(T& a, const U& b) {
    if (a >= b) return false;
    a = b;
    return true;
}
template <typename T, typename U>
bool chmin(T& a, const U& b) {
    if (a <= b) return false;
    a = b;
    return true;
}

void yes_no(bool f, string yes = "Yes", string no = "No") {
    cout << (f ? yes : no) << "\n";
}

void solve() {
    int n;
    cin >> n;
    vi g(n + 1);
    g[0] = g[1] = 0;
    REP(i, 2, n + 1) {
        set<int> st;
        st.emplace(g[i / 2] ^ g[(i + 1) / 2]);
        if (i >= 3) st.emplace(g[i / 3] ^ g[(i + 1) / 3] ^ g[(i + 2) / 3]);
        while (st.count(g[i])) ++g[i];
    }
    if (g[n] != 0) cout << "A" << '\n';
    else cout << "B" << '\n';
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int t = 1;
    // multi-testcase
    // cin >> t;
    rep(ti, t) solve();
    return 0;
}