#include <bits/stdc++.h>
using namespace std;

#define REP(i, n) for (int (i) = 0 ; (i) < (int)(n) ; ++(i))
#define REPN(i, m, n) for (int (i) = m ; (i) < (int)(n) ; ++(i))
#define REP_REV(i, n) for (int (i) = (int)(n) - 1 ; (i) >= 0 ; --(i))
#define REPN_REV(i, m, n) for (int (i) = (int)(n) - 1 ; (i) >= m ; --(i))

#define INF 2e9
#define INF_LL 1LL<<60
#define ll long long

typedef pair<ll, ll> P;

int nim[101]; 
/* nim[i]: 石がi個ある状態でのgrundy数 */

int main(){
    int n; cin >> n;

    nim[2] = 1;

    REPN(i, 3, n+1) {
        int a=0, b=0;

        if(i % 2 == 0) {
            a = nim[i/2]^nim[i/2];
        } else {
            a = nim[(i+1)/2];
            a ^= nim[(i-1)/2];
        }

        if(i % 3 == 0) {
            b = nim[i/3]^nim[i/3]^nim[i/3];
        } else if (i % 3 == 1) {
            b = nim[(i-1)/3]^nim[(i-1)/3];
            b ^= nim[(i+2)/3];
        } else {
            b = nim[(i-2)/3];
            b ^= nim[(i+1)/3]^nim[(i+1)/3];
        }

        if(b < a) {
            int tmp = b;
            b = a;
            a = tmp;    
        }

        REP(j, b+2) {
            if(j != a && j != b) {
                nim[i] = j;
                break;
            }
        }
    }

    if(nim[n] == 0) {
        cout << "B" << endl;
    } else {
        cout << "A" << endl;
    }

    
    return 0;
}