N = int(input())
D = 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991
D *= N
S = str(D)
ans = ""
if N <= 8:
    ans += "0."
    ans += S
elif 9 <= N <= 81:
    ans += S[0] + "."
    ans += S[1:]
else:
    ans += S[0:2] + "."
    ans += S[2:]
print(ans)