N = int(input())

ans = "0"
if N > 0:
    ans += "."
    ans += "142857"*(N//6)
for i in range(1, N%6+1):
    if i%6 == 1:
        ans += "1"
    elif i%6 == 2:
        ans += "4"
    elif i%6 == 3:
        ans += "2"
    elif i%6 == 4:
        ans += "8"
    else:
        ans += "5"
print(ans)