#include <bits/stdc++.h>
#define rep(i, a) for (int i = 0; i < (a); i++)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define repr(i, a) for (int i = (a) - 1; i >= 0; i--)
#define repr2(i, a, b) for (int i = (b) - 1; i >= (a); i--)
using namespace std;
typedef long long ll;
const ll inf = 1e9;
const ll mod = 1e9 + 7;

int dp[111];

int grundy(int n) {
	if (n <= 1) return 0;	
	if (dp[n] >= 0) return dp[n];
	set<int> s;
	s.insert(grundy(n / 2) ^ grundy((n + 1) / 2));
	s.insert(grundy(n / 3) ^ grundy((n + 1) / 3) ^ grundy((n + 2) / 3));
	int res = 0;
	while (s.count(res)) res++;
	return dp[n] = res;
}

int main() {
	memset(dp, -1, sizeof(dp));
	int N;
	cin >> N;

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

	return 0;
}