from decimal import Decimal

primes = [2, 3, 5, 7, 11, 13]
composites = [4, 6, 8, 9, 10, 12]

K = int(input())

if K == 0:
    print("0.000000000000000000")
else:
    count = 0
    for p in primes:
        for c in composites:
            if p * c == K:
                count += 1
    prob = Decimal(count) / Decimal(36)
    formatted_prob = format(prob, '.18f')
    print(formatted_prob)