#include <bits/stdc++.h>

using namespace std;

using ll = long long;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll n;
    cin >> n;
    vector<ll> a(n);
    for (int i = 0; i < n; i++) cin >> a[i];
    ll A = 0, A2 = 0, sum_i2 = 0;
    for (int i = 0; i < n; i++) {
        A += a[i];
        A2 += i * a[i];
        sum_i2 += i * i;
    }

    ll hoge = 2 * sum_i2 - (n - 1) * n / 2 * (n - 1);
    ll foo = 2 * A2 - A * (n - 1);
    double d = (double)foo / hoge;
    double b = (double)A / n - d * (n - 1) / 2;
    cout << fixed << setprecision(15) << b << " " << d << endl;
    double cost = 0;
    for (int i = 0; i < n; i++) {
        double x = b + d * i;
        x -= a[i];
        cost += x * x;
    }
    cout << fixed << setprecision(15) << cost << endl;
    return 0;
}