a = {}
b = {}
s = {} 
n = 1000
r = 0

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
	ap = 0 
	for j=1, n do
		if a[i] == b[j] then
			ap = ap + 1
		end
	end
	r = r + ap*a[i]
end

print(r)