#encoding:utf-8 No.0046 2014.10.6
height = []
while true
  data = gets.chomp
  if data == ""
    break
  end
  height.push data.to_f
end

max = height[0]
min = height[0]

height.length.times do |i|
  if max < height[i]
    max = height[i]
  elsif min > height[i]
    min = height[i]
  end
end

printf("%.1f\n",max-min)