题目描述
Takahashi made N problems for competitive programming. The problems are numbered 1 to N, and the difficulty of Problem i is represented as an integer d_i (the higher, the harder).
He is dividing the problems into two categories by choosing an integer K, as follows:
- A problem with difficulty K or higher will be for ARCs.
- A problem with difficulty lower than K will be for ABCs.
How many choices of the integer K make the number of problems for ARCs and the number of problems for ABCs the same?
- $2 \leq N \leq 10^5$
- N is an even number.
- $1 \leq d_i \leq 10^5$
- All values in input are integers.
Input
Input is given from Standard Input in the following format:
N
d_1 d_2 ... d_N
Output
Print the number of choices of the integer K that make the number of problems for ARCs and the number of problems for ABCs the same.
Examples
Input
6
9 1 4 4 6 7
Output
2
Input
8
9 1 14 5 5 4 4 14
Output
0
Input
14
99592 10342 29105 78532 83018 11639 92015 77204 30914 21912 34519 80835 100000 1
Output
42685
输入格式
见题面
输出格式
见题面