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.