[프로그래머스] 콜라츠 추측

def solution(n):
    i=0
    answer = 0
    while i < 500:
        if n == 1:
            break
        elif n % 2 == 0:
            n = n // 2
        else:
            n = 3 * n + 1
        i += 1
    if n == 1:
        answer = i
    else:
        answer = -1
    return answer