P24100 [AtCoder] Kaprekar Number
入门
题目描述

Problem Statement

For an integer x not less than 0, we define g_1(x), g_2(x), f(x) as follows:

  • g_1(x)= the integer obtained by rearranging the digits in the decimal notation of x in descending order
  • g_2(x)= the integer obtained by rearranging the digits in the decimal notation of x in ascending order
  • f(x)=g_1(x)-g_2(x)

For example, we have g_1(314)=431, g_2(3021)=123, f(271)=721-127=594. Note that the leading zeros are ignored.
Given integers N, K, find a_K in the sequence defined by a_0=N, a_{i+1}=f(a_i)\ $(i\geq 0)$.

Input

Input is given from Standard Input in the following format:
N K

Output

Print a_K.

Constraints

  • $0 \leq N \leq 10^9$
  • $0 \leq K \leq 10^5$
  • All values in input are integers.

Sample Input 1

314 2

Sample Output 1

693

We have:

  • a_0=314
  • a_1=f(314)=431-134=297
  • a_2=f(297)=972-279=693

Sample Input 2

1000000000 100

Sample Output 2

0

We have:

  • a_0=1000000000
  • a_1=f(1000000000)=1000000000-1=999999999
  • a_2=f(999999999)=999999999-999999999=0
  • a_3=f(0)=0-0=0
  • $\vdots$

Sample Input 3

6174 100000

Sample Output 3

6174

输入格式

见题面 Input 部分

输出格式

见题面 Output 部分

样例输入
314 2
样例输出
693