题目描述
Problem Statement
A positive integer X is said to be a lunlun number if and only if the following condition is satisfied:
- In the base ten representation of X (without leading zeros), for every pair of two adjacent digits, the absolute difference of those digits is at most 1.
For example, 1234, 1, and 334 are lunlun numbers, while none of 31415, 119, or 13579 is.
You are given a positive integer K. Find the K-th smallest lunlun number.
Input
Input is given from Standard Input in the following format:
K
Output
Print the answer.
Constraints
- $1 \leq K \leq 10^5$
- All values in input are integers.
Sample Input 1
15
Sample Output 1
23
We will list the 15 smallest lunlun numbers in ascending order:
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
21,
22,
23.
Thus, the answer is 23.
Sample Input 2
1
Sample Output 2
1
Sample Input 3
13
Sample Output 3
21
Sample Input 4
100000
Sample Output 4
3234566667
Note that the answer may not fit into the 32-bit signed integer type.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分