#include <bits/stdc++.h> 
using namespace std;
typedef long long ll;
ll INFL = 1000000000000000010;//10^18 = 2^60
int INF = 2000000000;//10^9
ll MOD  = 998244353;
vector<int> memo(110, -1);

int grundy(int N){
    if(memo.at(N) != -1) return memo.at(N);
    if(N == 1) return 0;
    if(N == 2) return 1;
    
    set<int> s;
    if(N % 2 == 0){
        s.insert(grundy(N/2) ^ grundy(N/2));
    }else{
        s.insert(grundy(N/2) ^ grundy(N/2+1));
    }
    
    
    if(N % 3 == 1){
        s.insert(grundy(N/3) ^ grundy(N/3) ^ grundy(N/3+1));
    }else if(N % 3 == 2){
        s.insert(grundy(N/3) ^ grundy(N/3+1) ^ grundy(N/3+1));
    }else{
        s.insert(grundy(N/3) ^ grundy(N/3) ^ grundy(N/3));
    }
    
    int res = 0;
    while(s.count(res)) res++;
    return memo.at(N) = res;
    
}

int main() {
    int N;
    cin >> N;
    if(grundy(N)){
        cout << "A" << endl;
    }else{
        cout << "B" << endl;
    }
    
}