#include <bits/stdc++.h>

using namespace std;

typedef pair<int,int> P;
typedef pair<int,pair<int,int>> PP;
typedef long long ll;

const double EPS = 1e-8;
const int INF = 1e9;
const int MOD = 1e9+7;

int dy[] = {0,1,0,-1};
int dx[] = {1,0,-1,0};

int memo[101];
int grundy(int x){
	if(memo[x] != -1)return memo[x];

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

	int res = 0;
	while(s.count(res))res++;
	return memo[x] = res;
}

int main(void) {
	fill(memo,memo+101,-1);
	int x;
	cin >> x;
	if(grundy(x) != 1)cout << "A" << endl;
	else cout << "B" << endl;

	return 0;
}