from decimal import Decimal, getcontext, ROUND_HALF_UP

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

K = int(input())

count = 0
for p in primes:
    for c in composites:
        if p * c == K:
            count += 1

if count == 0:
    print("0.00000000000000000")
else:
    getcontext().rounding = ROUND_HALF_UP
    prob = Decimal(count) / Decimal(36)
    formatted = format(prob, '.18f')
    print(formatted)