func main()
	var n: int :: cui@input().toInt(&)
	var A: []char :: cui@input()
	var B: []char :: cui@input()
	var ans: int
	for i(0, n - 1)
		do ans :+ A[i] = B[i] ?(0, 1)
	end for
	do cui@print("\{ans}\n")
end func