# Horse-racing Duals

Casablanca’s 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 program which, using a given number of strengths, identifies the
two closest strengths and shows their difference with an integer (≥ 0).

## Input

Line 1: Number N of horses

The N following lines: the strength P[i] of each horse. P[i] is an integer.

##Output

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

##Constraints

1 < N  < 100000
0 < P[i] ≤ 10000000