#include <bits/stdc++.h>

typedef long long ll;
typedef unsigned long long ull;

#define FOR(i,a,b) for(int (i)=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define RANGE(vec) (vec).begin(),(vec).end()

using namespace std;


class PilesOfStones {
public:
    // grundy 数で解く
    void solve(void) {
            int N;
            cin>>N;
            map<int,int> memo;
            function<int(int)> grundy = [&](int n) {
                if (memo.count(n))
                    return memo[n];
                if (n <= 1)
                    return 0;
                set<int> S;
                if (n%2 == 0)
                    S.insert(grundy(n/2) ^ grundy(n/2));
                if (n%2 == 1)
                    S.insert(grundy(n/2) ^ grundy(n/2+1));
                if (n%3 == 0)
                    S.insert(grundy(n/3) ^ grundy(n/3) ^ grundy(n/3));
                if (n%3 == 1)
                    S.insert(grundy(n/3) ^ grundy(n/3) ^ grundy(n/3+1));
                if (n%3 == 2)
                    S.insert(grundy(n/3) ^ grundy(n/3+1) ^ grundy(n/3+1));
                int res = 0;
                while (S.count(res))
                    ++res;
                return memo[n] = res;
            };
            if (grundy(N))
                cout<<"A"<<endl;
            else
                cout<<"B"<<endl;
    }
};

#if 1
int main(int argc, char *argv[])
{
        ios::sync_with_stdio(false);
        auto obj = new PilesOfStones();
        obj->solve();
        delete obj;
        return 0;
}
#endif