func main()
	var n: int :: cui@inputInt()
	var t: []int :: #[n]int
	for i(0, n - 1)
		do t[i] :: cui@inputInt()
	end for
	var s: []int :: #[n]int
	for i(0, n - 1)
		do s[i] :: cui@inputInt()
	end for
	
	var ans: int :: 0
	var next: int :: 0
	for i(0, n - 1)
		if(next <= s[i])
			do ans :+ 1
			do next :: s[i] + t[i]
		end if
	end for
	
	do cui@print("\{ans}\n")
end func