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

#define rep(i, n) for (int i = 0; i < (n); i ++)

int g[110];

int grundy(int x) {
        if (g[x] != -1) return g[x];
        if (x == 1) return g[x] = 0;
        set<int> s;
        if (x % 2 == 0 && x >= 2) s.insert(grundy(x / 2) ^ grundy(x / 2));
        if (x % 2 == 1 && x >= 3) s.insert(grundy(x / 2) ^ grundy(x / 2 + 1));
        if (x % 3 == 0 && x >= 3) s.insert(grundy(x / 3) ^ grundy(x / 3) ^ grundy(x / 3));
        if (x % 3 == 1 && x >= 4) s.insert(grundy(x / 3) ^ grundy(x / 3) ^ grundy(x / 3 + 1));
        if (x % 3 == 2 && x >= 5) s.insert(grundy(x / 3) ^ grundy(x / 3 + 1) ^ grundy(x / 3 + 1));
        int res = 0;
        while (s.count(res)) res ++;
        return g[x] = res;
}

int main() {
        int n;
        cin >> n;
        memset(g, -1, sizeof(g));
        if (grundy(n) == 0) cout << "B" << endl;
        else cout << "A" << endl;
        return 0;
}