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

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")
}

fn main() {
    let n: u32 = read();
    let mut h: i32 = read();
    let mut ai: Vec<u32> = Vec::new();
    let mut bi: Vec<u32> = Vec::new();

    for _ in 0..n {
        ai.push(read());
        bi.push(read());
    }

    let (_, &a_max) = ai.iter().enumerate().max_by_key(|&(_, &a)| a).unwrap();

    let mut ans: u32 = 0;
    for b in bi {
        if b > a_max {
            ans += 1;
            h -= b as i32;
        }
        if h <= 0 {
            break;
        }
    }
    if h > 0 {
        ans += h as u32 / a_max;
        if h as u32 % a_max > 0 {
            ans += 1;
        }
    }
    println!("{}", ans);
}
