#include <iostream>
#include <set>

using namespace std;

int memo[101], n;

int grundy(int x) {
	if (memo[x] != 0 || x == 1 || x == 2)return memo[x];
	set<int>s;
	if (x % 2 == 0) {
		s.insert(grundy(x / 2) ^ grundy(x / 2));
	}
	else {
		s.insert(grundy(x / 2) ^ grundy(x / 2 + 1));
	}
	if (x % 3 == 0) {
		s.insert(grundy(x / 3) ^ grundy(x / 3) ^ grundy(x / 3));
	}
	else if (x % 3 == 1) {
		s.insert(grundy(x / 3) ^ grundy(x / 3) ^ grundy(x / 3 + 1));
	}
	else {
		s.insert(grundy(x / 3) ^ grundy(x / 3 + 1) ^ grundy(x / 3 + 1));
	}
	int g = 0;
	while (s.count(g) != 0)g++;
	return memo[x] = g;
}

int main() {
	cin >> n;
	memo[1] = 0;
	memo[2] = 1;
	if (grundy(n)) {
		cout << "A" << endl;
	}
	else {
		cout << "B" << endl;
	}
}