#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

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

    using ld = long double;
    int N; cin >> N;
    vector<pair<ld,ld>> p(N);
    rep(i,N) {
        p[i].first = i;
        cin >> p[i].second;
    }

    ld X = 0, Y = 0, XY = 0, XX = 0;
    for(auto [x, y] : p) {
        X += x;
        Y += y;
        XY += x * y;
        XX += x * x;
    }

    ld a = (N * XY - X * Y) / (N * XX - X * X);
    ld b = (XX * Y - XY * X) / (N * XX - X * X);
    ld e = 0;
    rep(i,N) {
        auto [x, y] = p[i];
        ld y2 = a * i + b;
        e += (y - y2) * (y - y2);
    }
    cout << fixed << setprecision(20) << b << " " << a << "\n" << e << endl;
}