#include<bits/stdc++.h>
using namespace std;
using Int = long long;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}

//INSERT ABOVE HERE
Int dp[111];
Int dfs(Int x){
  if(x<=1) return dp[x]=0;
  Int &res=dp[x];
  if(~res) return res;
  res=0;
  set<Int> ss;
  if(x%2==0) ss.emplace(dfs(x/2)^dfs(x/2));
  if(x%2==1) ss.emplace(dfs(x/2)^dfs(x/2+1));
  if(x%3==0) ss.emplace(dfs(x/3)^dfs(x/3)^dfs(x/3));
  if(x%3==1) ss.emplace(dfs(x/3)^dfs(x/3)^dfs(x/3+1));
  if(x%3==2) ss.emplace(dfs(x/3)^dfs(x/3+1)^dfs(x/3+1));
  while(ss.count(res)) res++;
  return res;
}
signed main(){
  memset(dp,-1,sizeof(dp));
  Int n;
  cin>>n;  
  cout<<(dfs(n)?"A":"B")<<endl;
  return 0;
}