use proconio::input;
#[allow(unused)]
use proconio::marker::*;
#[allow(unused)]
use std::collections::*;

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

    let mut x = vec![];
    for &(a, b) in &ab {
        x.push((m - a + b - 1) / b);
    }

    x.sort();

    let mut l = 0;
    let mut r = 1 << 30;
    while r - l > 1 {
        let o = (r + l) / 2;
        let mut f = true;
        let mut i = 1;
        while f && i * o <= n {
            if x[i * o - 1] <= i {
                f = false;
            }
            i += 1;
        }
        if n % o > 0 && *x.last().unwrap() < i {
            f = false;
        }
        if f {
            r = o;
        } else {
            l = o;
        }
    }

    println!("{}", l);
}