#include<stdio.h>
int t[1003], s[1003];
int main()
{
    int n;
    scanf("%d", &n);
    int i;
    for (i = 0; i < n; i++)
        scanf("%d", &t[i]);
    for (i = 0; i < n; i++)
        scanf("%d", &s[i]);
    int ans = 0, time = 0;
    for (i = 0; i < n; i++)
    {
        if (s[i] < time)
            continue;
        ans++;
        time = s[i] + t[i];
    }
    printf("%d\n", ans);
    return 0;
}