#include <iostream>
#include <vector>
#include <iomanip>
using namespace std;

int main() {
    int N;
    cin >> N;
    vector<long long> a(N);
    for (int i = 0; i < N; ++i) {
        cin >> a[i];
    }
    long long sum_x = 0, sum_x2 = 0, sum_a = 0, sum_xa = 0;
    for (int k = 0; k < N; ++k) {
        sum_x += k;
        sum_x2 += (long long)k * k;
        sum_a += a[k];
        sum_xa += (long long)k * a[k];
    }
    double D = (double)N * sum_x2 - (double)sum_x * sum_x;
    double d = ((double)N * sum_xa - (double)sum_x * sum_a) / D;
    double b1 = ((double)sum_a * sum_x2 - (double)sum_x * sum_xa) / D;
    double cost = 0.0;
    for (int k = 0; k < N; ++k) {
        double diff = a[k] - (b1 + d * k);
        cost += diff * diff;
    }
    cout << fixed << setprecision(15);
    cout << b1 << " " << d << endl;
    cout << cost << endl;
    return 0;
}