#include <iostream>
#include <cstdio>
#include <set>
using namespace std;
typedef long long ll;
#define rep(i,n) for(int i=0;i<(n);i++)

int dp[110];

int grundy(int x){
    if(dp[x] != -1)return dp[x];
    if(x == 1)return dp[x] = 0;//負け状態

    set<int> s;
    //状態遷移先
    if(x % 2 == 0 && x >= 2) s.insert(grundy(x / 2) ^ grundy(x / 2));
    if(x % 2 == 1 && x >= 3) s.insert(grundy(x / 2) ^ grundy(x / 2 + 1));
    if(x % 3 == 0 && x >= 3) s.insert(grundy(x / 3) ^ grundy(x / 3) ^ grundy(x / 3));
    if(x % 3 == 1 && x >= 4) s.insert(grundy(x / 3) ^ grundy(x / 3) ^ grundy(x / 3 + 1));
    if(x % 3 == 2 && x >= 5) s.insert(grundy(x / 3) ^ grundy(x / 3 + 1) ^ grundy(x / 3 + 1));

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

int main(void){
    rep(i, 110) dp[i] = -1;
    int n; cin >> n;

    if(grundy(n) == 0){
        printf("B\n");
    }else{
        printf("A\n");
    }
    return 0;
}