n = int(input())
d = 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991
ans = d * n
s = str(ans)

if n <= 8:
    print("0." + s)
elif n <= 81:
    print(s[0] + '.' + s[1:])
else:
    print(s[0:2] + '.' + s[2:])