import sys
sys.setrecursionlimit(10**6)
import pypyjit
pypyjit.set_param('max_unroll_recursion=-1')

N = int(input())

def dfs(x,y):
    if x >= N:
        if x == N:
            print("".join(y))
            exit()
        return
    y.append("A")
    dfs(x*2+1,y)
    y.pop()
    y.append("B")
    dfs(x*3+1,y)
    y.pop()

dfs(1,[])