#define _USE_MATH_DEFINES
 
#include <iostream>
#include <iomanip>
#include <sstream>
 
#include <algorithm>
#include <cmath>
 
#include <string>
//#include <array>
#include <list>
#include <queue>
#include <vector>
#include <complex>
#include <set>
#include <map>
 
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
 
#define PII pair<int,int>
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////

int main(void){
    std::cin.tie(0); 
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    //cout << setprecision(16);//
	int N;
	cin>>N;

	int dp[101];
	rep(i,100){
		dp[i] = -1;
	}
	dp[1] = 0;
	dp[2] = 1;
	int temp3,temp2;
	for(int i=3;i<=N;++i){
		{
			temp3 = 0;
			rep(j,i%3){
				temp3 ^= dp[i/3+1];
			}
			rep(j,3-i%3){
				temp3 ^= dp[i/3];
			}
		}
		{
			temp2 = 0;
			temp2 ^= dp[i/2+i%2];
			temp2 ^= dp[i/2];
		}
		int s,b;
		s = min(temp2,temp3);
		b = max(temp2,temp3);
		if( s == b ){
			if(s==0){
				dp[i] = 1;
			}else{
				dp[i] = 0;
			}
		}else if(s > 0){
			dp[i] = 0;
		}else if(b > 1){
			dp[i] = 1;
		}else{
			dp[i] = 2;
		}
	}
	if( dp[N] != 0){
		P("A");
	}else{
		P("B");
	}
	return 0;
}