niz

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 position of the first occurrence of the decimal representation of number N in the sequence.

입력

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

출력

The first and only line of output should contain the position of the first occurrence of the decimal representation of number N in the sequence.

15

20

34

3

142

73