#[allow(unused_macros)]
macro_rules! get {
    ([$t:ty] ; $n:expr) => {
        (0..$n)
        .map(|_| get!([$t])).collect::<Vec<_>>()
    };
    ($($t:ty),+ ; $n:expr) => {
        (0..$n).map(|_| get!($($t),+)).collect::<Vec<_>>()
    };
    ([$t:ty]) => {
        rl().split_whitespace()
        .map(|x| x.parse().unwrap())
        .collect::<Vec<$t>>()
    };
    ($t:ty) => {
        rl().parse::<$t>().unwrap()
    };
    ($($t:ty),*) => {
        {
            let line =rl();
            let mut iter = line.split_whitespace();
            ($(iter.next().unwrap().parse::<$t>().unwrap()),*)
        }
    };
}
fn rl() -> String {
    let mut line = String::new();
    std::io::stdin().read_line(&mut line).unwrap();
    line.trim().to_string()
}

fn main() {
    let (n, hp) = get!(usize, i64);
    let mut hp = hp;
    let mut v = Vec::new();
    let mut count = 0;
    let mut max_slash = 0;
    let mut slash_weapon: usize = 0;
    for i in 0..n {
        let tmp = get!(i64, i64);
        if max_slash < tmp.0 {
            max_slash = tmp.0;
            slash_weapon = i;
        }
        v.push(tmp);
    }
    let mut throw_weapons = Vec::new();
    for (i, x) in v.iter().enumerate() {
        if v[slash_weapon].0 < x.1 && slash_weapon != i {
            throw_weapons.push(i);
        }
    }

    for i in throw_weapons.iter() {
        hp -= v[*i].1;
        count += 1;
    }
    if v[slash_weapon].1 <= v[slash_weapon].0 {
        count += (hp + v[slash_weapon].0 - 1) / v[slash_weapon].0;
    } else {
        count += 1;
        hp -= v[slash_weapon].1;
        count += (hp + v[slash_weapon].0 - 1) / v[slash_weapon].0;
    }

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