#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;
using ll = long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n;
    cin >> n;

    vector<int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }

    double x2 = 0, x = 0, xy = 0, y = 0;
    for (int i = 0; i < n; i++) {
        x2 += i * i;
        x += i;
        xy += i * a[i];
        y += a[i];
    }
    //x2 /= n;
    //x /= n;
    //xy /= n;
    //y /= n;

    double t = n * x2 - x * x;
    double d = (n * xy - x * y) / t;
    double b = (x2 * y - xy * x) / t;

    double c = 0;
    for (int i = 0; i < n; i++) {
        double t = d * i + b;
        double s = t - a[i];
        c += s * s;
    }

    printf("%.14f %.14f\n%.14f\n", b, d, c);

    return 0;
}