import sys
from decimal import Decimal, ROUND_HALF_UP

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

K = int(sys.stdin.readline())

count = 0

if K != 0:
    for p in prime_dice:
        for c in composite_dice:
            if p * c == K:
                count += 1

prob = Decimal(count) / Decimal(36)
rounded_prob = prob.quantize(Decimal('0.00000000000000000'), rounding=ROUND_HALF_UP)

print(rounded_prob)