#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[8]={1,-1,0,0,1,1,-1,-1};
const ll dx[8]={0,0,1,-1,1,-1,1,-1};
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
map<ll,ll> memo;
ll dfs(ll n){
    if(memo.count(n))return memo[n];
    ll g1=dfs(n/2)^dfs((n+1)/2);
    ll g2=dfs(n/3)^dfs((n+1)/3)^dfs((n+2)/3);
    rep(i,1000){
        if(i!=g1&&i!=g2){
            memo[n]=i;break;
        }
    }
    return memo[n];
}
int main(){
    ll n;cin >> n;
    memo[1]=0;memo[2]=1;
    cout << (dfs(n)? 'A':'B') <<endl;
}