n, m = map(int, input().split())

def count_p_in_factorial(n, p):
    count = 0
    while n > 0:
        n = n // p
        count += n
    return count

count_2 = count_p_in_factorial(n, 2)
count_5 = count_p_in_factorial(n, 5)

m_count_2 = 0
temp = m
while temp % 2 == 0 and temp != 0:
    m_count_2 += 1
    temp = temp // 2

m_count_5 = 0
temp = m
while temp % 5 == 0 and temp != 0:
    m_count_5 += 1
    temp = temp // 5

total_2 = count_2 + m_count_2
total_5 = count_5 + m_count_5

print(min(total_2, total_5))