use proconio::{fastout, input};

#[fastout]
fn main() {
    input! {
        n: usize,
        m: u32,
        plants: [(u32, u32); n],
    }

    println!("{}", output(solve(m, plants)));
}

fn prepare(m: u32, plants: Vec<(u32, u32)>) -> Vec<u32> {
    plants.into_iter().map(|(a, b)| (m - a) / b).collect()
}

fn solve(m: u32, plants: Vec<(u32, u32)>) -> u32 {
    let mut deadline_of = prepare(m, plants);
    deadline_of.sort_unstable();
    let deadline_of = deadline_of;

    let mut l = 0;
    let mut r = deadline_of.len();
    while l + 1 < r {
        let c = l.midpoint(r);
        if deadline_of
            .chunks(c)
            .enumerate()
            .all(|(i, d)| d[0] >= i as u32)
        {
            r = c;
        } else {
            l = c;
        }
    }
    r as u32
}

fn output(ans: u32) -> u32 {
    ans
}