use proconio::input;

fn main() {
    input! {
        n: usize, m: usize,
        ab: [(usize, usize); n],
    }

    let mut ng_day = ab.iter().map(|&(a, b)| (m - a) / b + 1).collect::<Vec<_>>();
    ng_day.sort_unstable();

    let mut rle: Vec<(usize, usize)> = vec![];
    for d in ng_day {
        if rle.last().is_some_and(|last| last.1 == d) {
            rle.last_mut().unwrap().0 += 1;
        } else {
            rle.push((1, d));
        }
    }

    let mut ans = 0;
    let mut cum = 0;
    for (cnt, day) in rle {
        cum += cnt;
        ans = ans.max((cum + day - 1) / day);
    }

    println!("{ans}");
}