use proconio::input;
fn main() {
    input! {
        n: usize,
        t: [usize; n],
        s: [usize; n]
    }
    let mut p = 0;
    let mut res = 0;
    for i in 0..n {
        if p < s[i] {
            p = s[i] + t[i] - 1;
            res += 1;
        }
    }
    println!("{}", res);
}