from collections import Counter
k = int(input())
p = [2, 3, 5, 7, 11, 13]
q = [4, 6, 8, 9, 10, 12]
r = []
for i in range(6):
    for j in range(6):
        r.append(p[i]*q[j])
r.sort()
co = Counter(r)
print(co[k]/len(r))