import sequtils,strutils
var
    N = stdin.readline.parseInt
    memo : array[101, int]
    flag : array[101, bool]
flag[1] = true
proc grundy(x : int) : int =
    if flag[x]:
        return memo[x]
    var
        g : array[7, bool]
        a : int
    if (x and 1) == 0 and x >= 2:
        g[0] = true
    if (x and 1) == 1 and x >= 3:
        g[grundy(x div 2) xor grundy(x div 2 + 1)] = true
    if x mod 3 == 0 and x >= 3:
        g[grundy(x div 3)] = true
    if x mod 3 == 1 and x >= 4:
        g[grundy(x div 3 + 1)] = true
    if x mod 3 == 2 and x >= 5:
        g[grundy(x div 3)] = true
    for i in 0..6:
        if g[i] == false:
            memo[x] = i
            flag[x] = true
            return i

if grundy(N) == 0:
    echo "B"
else:
    echo "A"