#include<iostream>
#include<set>


using namespace std;

int gr[110];

void init_grundy(){
	gr[1] = 0;
	for(int i = 2; i < 110; i++) gr[i] = -1;
}

int grundy(int x){
	if(gr[x] >= 0) return gr[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){
		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 res = 0;
	while(s.find(res) != s.end()) res++;
	return gr[x] = res;
}

int main(){
	int n, ans = 0;
	cin >> n;
	init_grundy();
	if(grundy(n)){
		cout << "A" << endl;
	}else{
		cout << "B" << endl;
	}
	return 0;
}