def f(n):
    s = ''
    while n > 0:
        s += str(n % 5)
        n //= 5
    s = s[::-1]
    return s
n = 5**2004 - 5**1016 - 25**508 - 5**400 + 25**250 - 27
b = f(n)
print(b.count('4'))