#! ruby
# yukicoder My Practice
# author: Leonardone @ NEETSDKASU

N = gets.to_i
X = gets.chomp.split.map(&:to_i)

x = X.sort.uniq

if x.size > 1
    puts x.zip(x.rotate(1)).map{|x,y| (x - y).abs}[0...-1].min
else
    puts 0
end