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Contest: Task: Related: TaskB TaskD

Score : $300$ points

Problem Statement

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?

Problem Statement

  • $2 \leq N \leq 10^5$
  • $N$ 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.

Sample Input 1

6
9 1 4 4 6 7

Sample Output 1

2

If we choose $K=5$ or $6$, Problem $1$, $5$, and $6$ will be for ARCs, Problem $2$, $3$, and $4$ will be for ABCs, and the objective is achieved. Thus, the answer is $2$.

Sample Input 2

8
9 1 14 5 5 4 4 14

Sample Output 2

0

There may be no choice of the integer $K$ that make the number of problems for ARCs and the number of problems for ABCs the same.

Sample Input 3

14
99592 10342 29105 78532 83018 11639 92015 77204 30914 21912 34519 80835 100000 1

Sample Output 3

42685