#ifdef ONLINE_JUDGE
#define NDEBUG
#endif
#if defined(__GNUC__) && !defined(__clang__)
// #pragma GCC optimize("O3")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#pragma GCC optimize("unroll-loops")
#endif

#include <bits/stdc++.h>
using namespace std;
#if __cplusplus >= 202002L
namespace R = ranges;
namespace V = views;
#endif
using i64 = long long;
using u64 = unsigned long long;
using f64 = double;
using uz = size_t;
using u32 = uint32_t;
using itn = int;

template <typename T> using ve = vector<T>;
template <typename T> using a2 = array<T, 2>;
template <typename K, typename V> using HashMap = unordered_map<K, V>;
template <typename T> using HashSet = unordered_set<T>;
template <typename T, typename C = less<T>>
using PQ = std::priority_queue<T, vector<T>, C>;
template <typename T, typename C = greater<T>>
using miPQ = std::priority_queue<T, vector<T>, C>;

#define mt make_tuple
#define mp make_pair

#ifdef LOCAL
#include "debug_template.cpp"
#else
#define debug(...)
#define debugArr(...)
#endif

// constexpr array<int, 5> dirs{-1, 0, 1, 0, -1};
// constexpr char nesw[4]{'N', 'E', 'S', 'W'};
// constexpr int M = 1e9 + 7;
void cln() { cout << '\n'; }
constexpr char ln = '\n';

array<int, 101> dp;

int main() {
#ifndef LOCAL
  ios::sync_with_stdio(0), cin.tie(0);
#endif
  //
  dp[2] = 1;
  for (unsigned int i = 3; i < 101; ++i) {
    bitset<10> in(UINT_MAX);
    in.reset(dp[i / 3 + (i % 3 == 1)]);
    int futatsuwake = 0;
    if (i & 1) {
      futatsuwake = dp[i / 2] ^ dp[i / 2 + 1];
    }
    in.reset(futatsuwake);
    dp[i] = in._Find_first();
  }

  int n;
  cin >> n;
  cout << (dp[n] ? 'A' : 'B') << ln;
}