Giải bài trực tuyến

During a meeting with professors in the Asian Confederation of Mathematics, a Russian professor came up with a problem:

He choose a number N (1 ≤ N ≤ 10¹⁸), then write all the numbers from 1 to N to form a continuous string of digits. Next he replaced substrings of identical digits with a single digit. For example string fragment "14445556677666" would be changed to "145676". Then he asked his fellow professors: given a length of string S determine the number N which results in that kind of string S. Can you help the professors?

Your task: write a program to help your country's mathematicians.

Input

A single number M, length of the string S (1 ≤ M ≤ 10¹⁸.)

Output

A single number N, the number which Russian professor selected.

Example

Input:
13

Output:
12

Explanation:

With N = 12, we get the string: 123456789101112.

Because there are three consecutive number ones, we delete the first two numbers, then we have: 1234567891012. The length of this string is 13