#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
using namespace std;

#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP(i,n,0)
#define REP(i,s,e) for (i = s; i < e; i++)
#define rep(i,n) REP(i,0,n)
#define INF 1e8

typedef long long ll;

int main() {
    int i, n;
    int grundy[101];
    cin >> n;
    grundy[1] = 0;
    REP (i,2,n+1) {
        set<int> s;
        s.insert(grundy[i/2]^grundy[(i+1)/2]);
        if (i >= 3)
            s.insert(grundy[i/3] ^ grundy[(i+1)/3] ^ grundy[(i+2)/3]);
        int res = 0;
        while (s.count(res)) res++;
        grundy[i] = res;
    }
    if (grundy[n])
        cout << 'A' << endl;
    else
        cout << 'B' << endl;
    return 0;
}