# 2
def lcm(a,b):
    m = a*b
    while a != 0 and b != 0:
        if a > b:
            a %= b
        else:
            b %= a
    return m // (a+b)


# 3
def fib(n):
    return round(((1 + 5 ** 0.5) / 2)**n / 5 ** 0.5)