p02989 AtCoder Beginner Contest 132 - Divide the Problems
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
```python
n = int(input())
q= sorted(list(map(int,input().split())))
print(q[n//2]-q[n//2-1])

```