fn getline() -> String {
    let mut __ret = String::new();
    std::io::stdin().read_line(&mut __ret).ok();
    return __ret.trim_end().to_string();
}

struct Input {
    _n: usize,
    h: usize,
    p: Vec<(usize, usize)>,
}

fn input() -> Input {
    let n = getline().parse::<usize>().unwrap();
    let h = getline().parse::<usize>().unwrap();
    // let h = getline().parse::<usize>().unwrap();
    let mut p = Vec::new();
    for _ in 0..n {
        let s = getline();
        let v = s
            .split(' ')
            .map(|v| v.parse::<usize>().unwrap())
            .collect::<Vec<_>>();
        p.push((v[0], v[1]));
    }

    Input { _n: n, h, p }
}

fn l(Input { _n: _, h, p }: &Input, a1: f64, a2: f64) -> f64 {
    let f = |x: f64| a1 * x + (*h as f64);
    let g = |x: f64| a2 * x;

    p.iter()
        .map(|(xi, yi)| {
            let f_diff = ((*yi as f64) - f((*xi) as f64)).powi(2);
            let g_diff = ((*yi as f64) - g((*xi) as f64)).powi(2);
            f_diff.min(g_diff)
        })
        .sum()
}

fn newton(input: &Input, x: f64, y: f64) -> (f64, f64) {
    let l_x = (l(input, x + H, y) - l(input, x - H, y)) / (2.0 * H);
    let l_y = (l(input, x, y + H) - l(input, x, y - H)) / (2.0 * H);
    let l_xx = (l(input, x + H, y) - 2.0 * l(input, x, y) + l(input, x - H, y)) / (H.powi(2));
    let l_yy = (l(input, x, y + H) - 2.0 * l(input, x, y) + l(input, x, y - H)) / (H.powi(2));
    let l_xy = (l(input, x + H, y) + l(input, x - H, y) + l(input, x, y + H) + l(input, x, y - H)
        - 2.0 * l(input, x, y)
        - l(input, x + H, y + H)
        - l(input, x - H, y - H))
        / (2.0 * H.powi(2));
    let l_yx = l_xy;

    let k = 1.0 / (l_xx * l_yy - l_xy * l_yx);
    let new_x = x - k * (l_yy * l_x - l_xy * l_y);
    let new_y = y - k * (-l_yx * l_x + l_xx * l_y);
    (new_x, new_y)
}

const H: f64 = 0.01;
const N: usize = 10;

fn main() {
    let i = input();
    let (mut a1, mut a2) = (-0.5, 0.5);

    for _ in 0..N {
        (a1, a2) = newton(&i, a1, a2)
    }

    println!("{:?}", l(&i, a1, a2));
}