fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();
    let mut a = String::new();
    std::io::stdin().read_line(&mut a).ok();
    let a: Vec<f64> = a.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();

    let xsum = n * (n-1) / 2;
    let xsum = xsum as f64;
    let ysum = a.iter().sum::<f64>();
    let x2sum = (0..n).map(|i| i*i).sum::<usize>() as f64;
    let xysum = (0..n).map(|i| i as f64 * a[i]).sum::<f64>();
    let denom = n as f64 * x2sum - xsum * xsum;
    let d = (n as f64 * xysum - xsum * ysum) / denom;
    let x = (x2sum * ysum - xysum * xsum) / denom;
    let cost = (0..n).map(|i| (a[i] - d*i as f64 - x).powf(2.)).sum::<f64>();
    println!("{} {}", x, d);
    println!("{}", cost);
}