from decimal import Decimal, getcontext

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

K = int(input())

count = 0
for p in prime:
    for c in composite:
        if p * c == K:
            count += 1

if count == 0:
    print("0.000000000000000000")
else:
    getcontext().prec = 20
    prob = Decimal(count) / Decimal(36)
    print("{0:.18f}".format(prob))