#include <bits/stdc++.h>
#define MOD 1000000007LL
using namespace std;
typedef long long ll;
typedef pair<int,int> P;

int dp[101];

int solve(int v){
	if(dp[v]!=-1)return dp[v];
	set<int> si;
	si.insert(solve(v/2)^solve((v+1)/2));
	si.insert(solve(v/3)^solve((v+1)/3)^solve((v+2)/3));
	int res=0;
	for(set<int>::iterator it=si.begin();it!=si.end();it++){
		if((*it)!=res)break;
		res++;
	}
	dp[v]=res;
	return res;
}

int main(void){
	int n;
	memset(dp,-1,sizeof(dp));
	dp[1]=0;
	dp[2]=1;
	scanf("%d",&n);
	printf("%s\n",(solve(n)!=0)?"A":"B");
	return 0;
}