#include <bits/stdc++.h>
using namespace std;

using int64 = long long;
using uint64 = unsigned long long;

double mean(vector<int64>& seq)
{
    double sum = 0.0;
    for (auto e : seq)
    {
        sum += e;
    }
    return sum / seq.size();
}

double sd(vector<int64>& seq)
{
    double sum = 0.0;
    for (auto e : seq)
    {
        sum += e * e;
    }
    return sqrt(sum / seq.size() - pow(mean(seq), 2));
}

double cov(vector<int64>& x, vector<int64>& y)
{
    double sum = 0.0,
           xmean = mean(x),
           ymean = mean(y);
    for (int i = 0; i < (int)x.size(); i++)
    {
        sum += (x[i] - xmean) * (y[i] - ymean);
    }
    return sum / x.size();
}

int main()
{
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int N;
    cin >> N;

    vector<int64> x(N), y(N);
    for (int i = 0; i < N; i++)
    {
        cin >> y[i];
        x[i] = i;
    }

    double A = cov(x, y) / pow(sd(x), 2),
           B = mean(y) - A * mean(x),
           error = 0.0;
    
    for (int i = 0; i < N; i++)
    {
        error += pow(y[i] - (B + A * i), 2);
    }

    cout << fixed << setprecision(10) << B << " " << A << endl;
    cout << fixed << setprecision(10) << error << endl;

    return 0;
}