#include "bits/stdc++.h"
using namespace std;

int dp[103];

int main() {
	int N;
	cin >> N;
	dp[0] = dp[1] = 0;
	for (int i = 2; i <= N; i++)
	{
		dp[i] = 0;
		set<int> s;
		s.insert(dp[i / 2] ^ dp[(i + 1) / 2]);
		if (i >= 3)s.insert(dp[i / 3] ^ dp[(i + 1) / 3] ^ dp[(i + 2) / 3]);
		while (s.find(dp[i]) != s.end()) dp[i]++;
	}
	if (dp[N] == 0) cout << "B" << endl;
	else cout << "A" << endl;
}