# Horse Racing Duals

A Hippodrome is organizing a new type of horse racing: duals. During a dual, only two horses will participate in the race. In order for the race to be interesting, it is necessary to try to select two horses with similar strength.

Write a solution which, using a given number of strengths, identify the two horses with the closest strengths and shows their difference with an integer `(≥ 0)`.

### Game Input

Input:

There are `N` horses. Array `arr` holds the strength `Pi` of each horse where `Pi` is an integer. The length of `arr` is `N`.

Output:

The difference `D` between the two closest strengths. `D` is an integer greater than or equal to `0`.

Constraints:

1 < `N` < 100000
0 < `Pi` ≤ 10000000

### Example

Input : `[3, 5, 8, 9]`
3 -> Which equals to `N`.
5 -> Which equals to `Pi` of first horse.
8 -> Which equals to `Pi` of second horse.
9 -> Which equals to `Pi` of third horse.

Output : `1`
1 -> The difference between the two closest strengths (8 and 9)

Contributed by Erkan Ercan