CF271A.Beautiful Year

It seems like the year of 2013 came only yesterday. Do you know a curious fact? The year of 2013 is the first year after the old 1987 with only distinct digits.

Now you are suggested to solve the following problem: given a year number, find the minimum year number which is strictly larger than the given one and has only distinct digits.

似乎2013年就在昨天。你知道一个有趣的事实吗？2013年是继1987年之后首个各位数字互不相同的年份。

现在请你解决如下问题：给定一个年份，找出严格大于该年份的最小年份，且其各位数字互不相同。

The single line contains integer y (1000 ≤ y ≤ 9000) — the year number.

单行输入包含一个整数 $y$（$1000 \leq y \leq 9000$）——年份。

Print a single integer — the minimum year number that is strictly larger than y and all it's digits are distinct. It is guaranteed that the answer exists.

输出一个整数——严格大于 y 的最小年份，且该年份的所有数字互不相同。保证答案存在。