N = eval(input())

number = 10**N
set1 = "142857"
mod = N%7
dif = N//7

if N < 7:
        tmp = set1[0:N]
else:
        tmp = set1
        for it in range(dif-1):
                tmp = tmp + set1
        tmp = tmp + set1[0:mod+1]

print(eval(tmp)/number)