Next Test

题意翻译

### 题面描述 给出 $n$ 个互不相同的整数 $a_i$ ，从小到大找第一个没有出现过的整数。 ### 输入格式 第一行一个正整数 $n$ ，之后是 $n$ 个整数 $a_i$ 。 ### 输出格式 一个整数 $x$ ，即第一个没有出现过的整数。 ### 数据范围与约定 $1\leq n\leq 3000$ $1\leq a_i\leq 3000$

题目描述

«Polygon» is a system which allows to create programming tasks in a simple and professional way. When you add a test to the problem, the corresponding form asks you for the test index. As in most cases it is clear which index the next test will have, the system suggests the default value of the index. It is calculated as the smallest positive integer which is not used as an index for some previously added test. You are to implement this feature. Create a program which determines the default index of the next test, given the indexes of the previously added tests.

输入输出格式

输入格式

The first line contains one integer $ n $ ( $ 1<=n<=3000 $ ) — the amount of previously added tests. The second line contains $ n $ distinct integers $ a_{1},a_{2},...,a_{n} $ ( $ 1<=a_{i}<=3000 $ ) — indexes of these tests.

输出格式

Output the required default value for the next test index.

输入输出样例

输入样例 #1

3
1 7 2

输出样例 #1

3