Kertoma

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

from math import ceil, log
import math

def get_log10_power_of_n_factorial(n):
    thisislog10 = 0
    for i in range(1, n+1):
        thisislog10 += log(i, 10)
    return thisislog10

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

s = sum(counts)

if(s < 10):
    for i in range(100):
        if get_counts(math.factorial(i)) == counts:
            print(i)
            break
else:
    for i in range(60010):
        if(s == ceil(get_log10_power_of_n_factorial(i))):
            print(i)
            break