#include <bits/stdc++.h>

using namespace std;

template<typename T> class Grundy {
private:
  map<T, int> grundy;

  template<typename S> int solve(S s) {
    int g = 0;
    for (auto t : s) g ^= solve(t);
    return g;
  }

public:
  int solve(T t) {
    if (grundy.count(t)) return grundy[t];
    set<int> s;
    for (auto g : t.next()) s.insert(solve(g));
    for (int i = 0; ; ++i) {
      if (s.count(i) == 0) return grundy[t] = i;
    }
  }
};

class State {
private:
  int n;

public:
  State (int n) : n(n) {}

  vector<vector<State>> next() {
    vector<vector<State>> v;
    if (n >= 2) v.emplace_back(vector<State>({State(n / 2), State((n + 1) / 2)}));
    if (n >= 3) v.emplace_back(vector<State>({State(n / 3), State((n + 1) / 3), State((n + 2) / 3)}));
    return v;
  }

  bool operator<(const State& state) const {
    return n < state.n;
  }
};

int main() {
  int n;
  cin >> n;
  Grundy<State> grundy;
  cout << (grundy.solve(State(n)) ? "A" : "B") << endl;
}