#include<stdio.h>

void run(void){
  int n;
  scanf("%d",&n);
  int g[101];
  g[0]=g[1]=0;
  g[2]=1;
  for(int i=3;i<=n;i++){
    int u[4]={0};
    int a=i/2;
    int b=i-a;
    u[g[a]^g[b]]=1;
    a=i/3;
    b=(i-a)/2;
    int c=i-a-b;
    u[g[a]^g[b]^g[c]]=1;
    int k=0;
    while(u[k]) k++;
    g[i]=k;
  }
  puts(g[n]?"A":"B");
}

int main(void){
  run();
  return 0;
}