import java.util.*;

public class judgeServer {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        sc.nextLine();

        int[] T = new int[N];
        int[] s = new int[N];

        for(int i = 0; i < N; i++){
            T[i] = sc.nextInt();
        }
        sc.nextLine();

        for(int i = 0; i < N; i++){
            s[i] = sc.nextInt();
        }

        int count = 0;
        int wait = 0;

        for(int i = 0; i < N; i++){
            if(wait <= s[i]){
                count += 1;
                wait = s[i] + T[i];
            }    
        }

        System.out.println(count);

        sc.close();
    }
}