use std::io::*;
use std::str::FromStr;

pub fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let stdin = stdin.lock();
    let token: String = stdin
        .bytes()
        .map(|c| c.expect("failed to read char") as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().expect("failed to parse token")
}

use std::cmp::max;

fn main() {
    let n: usize = read();
    let h: i64 = read();
    let mut av: Vec<i64> = vec![];
    let mut bv: Vec<i64> = vec![];

    for _ in 0..n {
        let a = read();
        let b = read();
        av.push(a);
        bv.push(b);
    }

    let mut maxa = 0;

    for i in 0..av.len() {
        let ai = av[i];
        maxa = max(maxa, ai);
    }

    let mut bnage = 0;
    let mut bcnt = 0;

    for i in 0..bv.len() {
        let bi = bv[i];
        if bi > maxa {
            bnage += bi;
            bcnt += 1;
        }
    }

    if bnage >= h {
        println!("{}", bcnt);
        return;
    }
    println!(
        "{}",
        (h - bnage) / maxa + if (h - bnage) % maxa == 0 { 0 } else { 1 } + bcnt
    );
}
