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.
n = int(input())

res = 0


t = [0] * 10
r = [0] * 10
for i in range(1, 10):
    t[i] = t[i - 1] + 9 * 10 ** (i - 1)
    r[i] = r[i - 1] + (9 * 10 ** (i - 1)) * i
    
l = [n > t[i] for i in range(10)]

for i in range(10):
    if not l[i]:
        res += r[i - 1] + (n - t[i - 1]) * (i)
        break
        
print(res)

