n = int(input())
d = 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991
a = str(d * n)
s = ""
if n <= 8:
    s = "0." + str(a)
if 9 <= n <= 81:
    s = a[0:1] + "." + a[1:]
if n >= 82:
    s = a[0:2] + "." + a[2:]
print(s)