from lib_misc import product


def get_irrational_fraction(digits_max):
    s = []
    n = 1
    digits = 0
    while digits < digits_max:
        s.append(str(n))
        digits += len(str(n))
        n += 1
    return "".join(s)


def euler_040():
    f = get_irrational_fraction(1000001)
    return product(map(int, [f[10**i - 1] for i in range(7)]))


if __name__ == "__main__":
    print("e040.py: " + str(euler_040()))
    assert(euler_040() == 210)