#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> VI;
typedef vector<VI> VVI;
#define REP(i, n)           for(int(i)=0;(i)<(n);++(i))
#define FOR(i, f, t)        for(int(i)=(f);(i)<(t);(++i))
#define RREP(i, n)          for(int(i)=(n)-1;(i)>=0;--(i))
const int MOD = int(1e9+7);

int N,M,W,H;
int res = 0;

const int MAXN = 100;
int dp[MAXN+1];
int solve(const int n){
    if(n == 1) return 0;
    if(dp[n] >= 0) return dp[n];

    int m1,m2,m3,v1=0,v2=0,k[2];
    m1 = n/2, m2 = n-m1;
    k[0]=k[1]=0;
    k[solve(m1)]++;
    k[solve(m2)]++;
    if(m1 == 1 && m2 == 1) v1 = 1;
    if(k[0]%2 == 1) v1 = 1;

    if(n>=3){
        m1 = n/3, m2 = (n-m1)/2, m3 = n-m1-m2;
        k[0]=k[1]=0;
        k[solve(m1)]++;
        k[solve(m2)]++;
        k[solve(m3)]++;
        if(m1 == 1 && m2 == 1 && m3 == 1) v1 = 1;
        if(k[0]%2 == 1) v2 = 1;
    }

    return dp[n] = v1|v2;
}

int main(){
    memset(dp,-1,sizeof(dp));
    int N; cin >> N;
    cout << (solve(N)?"A":"B") << endl;
}