#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<cctype>
#include<math.h>
#include<string>
#include<string.h>
#include<stack>
#include<queue>
#include<vector>
#include<utility>
#include<set>
#include<map>
#include<stdlib.h>
#include<iomanip>

using namespace std;

#define ll long long
#define ld long double
#define EPS 0.0000000001
#define INF 1e9
#define LINF (ll)INF*INF
#define MOD 1000000007
#define rep(i,n) for(int i=0;i<(n);i++)
#define loop(i,a,n) for(int i=a;i<(n);i++)
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)

#define int ll //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int,int> pii;
typedef vector<pii> vp;

int gcd(int a, int b){
    if(b==0) return a;
    return gcd(b,a%b);
}
int lcm(int a, int b){
    return a/gcd(a,b)*b;
}

vi grundy;

int f(int n){
    if(grundy[n] != -1)return grundy[n];
    if(n <= 1)return grundy[n] = 0;
    set<int> st;
    if(n%2){
        st.insert(f(n/2)^f(n/2+1));
    }else{
        st.insert(f(n/2)^f(n/2));
    }
    if(n%3 == 0){
        st.insert(f(n/3)^f(n/3)^f(n/3));
    }else if(n%3 == 1){
        st.insert(f(n/3+1)^f(n/3)^f(n/3));
    }else{
        st.insert(f(n/3+1)^f(n/3+1)^f(n/3));
    }
    int g = 0;
    while(st.count(g))g++;
    return grundy[n] = g;
}

signed main(void) {
    int n;
    cin >> n;
    grundy = vi(n+1,-1);
    if(f(n))cout << "A" << endl;
    else cout << "B" << endl;

}