#include<bits/stdc++.h>
using namespace std;
const int M = 1000000007;

int main() {
    int n;
    cin >> n;
    assert(2 <= n && n <= 1000);
    vector<int> a(n);
    double s1 = (n - 1) * n / 2;
    double s2 = (n - 1) * n * (2 * n - 1) / 6;
    double sa1 = 0, sa2 = 0;
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
        assert(0 <= a[i] && a[i] <= 100000);
        sa1 += a[i];
        sa2 += a[i] * i;
    }
    double b = (s2 * sa1 - s1 * sa2) / (n * s2 - s1 * s1);
    double d = (-s1 * sa1 + n * sa2) / (n * s2 - s1 * s1);
    double c = 0;
    for (int i = 0; i < n; ++i)
        c += (a[i] - (b + d * i)) * (a[i] - (b + d * i));

    cout << setprecision(9) << b << " " << d << "\n" << c << "\n";
    return 0;
}