Vanya got an important task — he should enumerate books in the library and label each book with its number. Each of the *n* books should be assigned with a number from 1 to *n*. Naturally, distinct books should be assigned distinct numbers.

Vanya wants to know how many digits he will have to write down as he labels the books.
The first line contains integer *n* (1 ≤ *n* ≤ 10<sup class="upper-index">9</sup>) — the number of books in the library.
inp = int(input())
ans = 0
var = 9
ans = 0
num = 1
while inp > 0:
	ans += min(inp,var)*num
	inp -= ans
	num += 1
print(ans)