broj

문제

A sequence of digits is obtained by writing down decimal representations of all integers starting with 1 and continuing up to a certain number N consecutively like this:

12345678910111213141516171819202122 ... etc.

Write a program that will compute the number of digits in such a sequence.

입력

The first and only line of input contains an integer N, 1 ≤ N ≤ 100,000,000.

출력

The first and only line of output should contain the number of digits in a sequence determined by the number given in the input.

5

5

15

21

120

252