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.
import sys
import math
import bisect

def solve(n):
    ans = 0
    for i in range(10):
        low = 10 ** i
        if n >= low:
            val = n - low + 1
        else:
            val = 0
        ans += val
        #print('n: %d, i: %d, low: %d, val: %d, ans: %d' % (n, i, low, val, ans))
    return ans

def main():
    n = int(input())
    ans = solve(n)
    print(ans)

if __name__ == "__main__":
    main()
