gets
arr = gets.split.map(&:to_i).sort
min = 1000001
(1...arr.size - 1).each do |i|
        min = (arr[i-1] - arr[i]).abs if (arr[i-1] - arr[i]).abs != 0 && (arr[i-1] - arr[i]).abs < min
        min = (arr[i+1] - arr[i]).abs if (arr[i+1] - arr[i]).abs != 0 && (arr[i+1] - arr[i]).abs < min
end
puts min == 1000001 ? 0 : min