a = [2, 3, 5, 7, 11, 13]
b = [4, 6, 8, 9, 10, 12]
cnt = 0
K = int(input())
for i in range(6):
    for j in range(6):
        if a[i]*b[j]==K:
            cnt+=1
print('{:.12f}'.format(cnt/36))