Kertoma

import math
counts = [int(x) for x in input().split(" ")]

def get_counts(num):
    nums = [0] * 10
    for i in str(num):
        nums[int(i)] += 1
    return nums

for i in range(101):
    my_counts = get_counts(math.factorial(i))
    if counts == my_counts:
        print(i)
        break