a = {}
b = {}
s = 0
n = 6

for i=1,n*2 do
	if i % 2 == 1 then
		table.insert(a, io.read("*n"))
	else
		table.insert(b, io.read("*n"))
	end
end

table.sort(a)
table.sort(b)

for i=1, n do
	s = s + math.abs(a[i] - b[i])	
end

print(s)