#include <iostream>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>
#include <list>
#include <vector>
#include <complex>
#include <utility>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <bitset>
#include <ctime>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <cassert>
#include <cstddef>
#include <iomanip>
#include <numeric>
#include <tuple>
#include <sstream>
#include <fstream>

using namespace std;
#define REP(i, n) for (int (i) = 0; (i) < (n); (i)++)
#define FOR(i, a, b) for (int (i) = (a); (i) < (b); (i)++)
#define RREP(i, a) for(int (i) = (a) - 1; (i) >= 0; (i)--)
#define FORR(i, a, b) for(int (i) = (a) - 1; (i) >= (b); (i)--)
#define DEBUG(C) cerr << #C << " = " << C << endl;
using LL = long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<LL>;
using VVL = vector<VL>;
using VD = vector<double>;
using VVD = vector<VD>;
using PII = pair<int, int>;
using PDD = pair<double, double>;
using PLL = pair<LL, LL>;
using VPII = vector<PII>;
template<typename T> using VT = vector<T>;
#define ALL(a) begin((a)), end((a))
#define RALL(a) rbegin((a)), rend((a))
#define SORT(a) sort(ALL((a)))
#define RSORT(a) sort(RALL((a)))
#define REVERSE(a) reverse(ALL((a)))
#define MP make_pair
#define FORE(a, b) for (auto &&a : (b))
#define FIND(s, e) ((s).find(e) != (s).end())
#define EB emplace_back

const int INF = 1e9;
const int MOD = INF + 7;
const LL LLINF = 1e18;

int N;
int grandy[110];

int calcGrandy(int n) {
    int &now = grandy[n];
    if (now != -1) return now;
    if (n == 0) return now = 0;
    set<int> se;
    if (n >= 2) {
        se.insert(calcGrandy(n / 2));
        if (n % 2) se.insert(calcGrandy((n / 2) + 1));
    }
    if (n >= 3) {
        se.insert(calcGrandy(n / 3));
        if (n % 3) se.insert(calcGrandy((n / 3) + 1));
    }
    now = 0;
    while (FIND(se, now)) now++;
    return now;
}

int main(void) {
    REP(i, 110) grandy[i] = -1;
    cin >> N;
    if (N == 1 || N == 3) {
        cout << "B" << endl;
        return 0;
    }
    if (N == 2) {
        cout << "A" << endl;
        return 0;
    }
    calcGrandy(N);
    bool ok = false;
    if (N % 2 == 0) {
        ok |= ((grandy[N / 2] ^ grandy[N / 2]) == 0);
    } else {
        ok |= ((grandy[N / 2] ^ grandy[(N / 2) + 1]) == 0);
    }
    if (N % 3 == 0) {
        ok |= ((grandy[N / 3] ^ grandy[N / 3] ^ grandy[N / 3]) == 0);
    } else if (N % 3 == 1) {
        ok |= ((grandy[(N / 3) + 1] ^ grandy[N / 3] ^ grandy[N / 3]) == 0);
    } else {
        ok |= ((grandy[(N / 3) + 1] ^ grandy[(N / 3) + 1] ^ grandy[N / 3]) == 0);
    }
    cout << (ok ? "A" : "B") << endl;
}