汉诺塔

count = 0
def hanoi(n, src, dst, mid):
    global count
    if n == 1:
        print("{}:{}->{}".format(1,src,dst))
        count += 1
    else :
        hanoi(n-1, src, mid, dst)
        print("{}:{}->{}".format(n,src,dst))
        count += 1
        hanoi(n-1, mid, dst, src)
hanoi(eval(input()),"A","C","B")
print(count)