#include <iostream>
#include <iomanip>
#include <vector>

using ldouble = long double;

void solve() {
    int n;
    std::cin >> n;

    ldouble isum = 0, iisum = 0,
            asum = 0, aisum = 0;

    std::vector<ldouble> as(n);
    for (int i = 0; i < n; ++i) {
        isum += i;
        iisum += i * i;

        auto& a = as[i];
        std::cin >> a;
        asum += a;
        aisum += a * i;
    }

    ldouble b = (iisum * asum - aisum * isum) / (n * iisum - isum * isum);
    ldouble d = (n * aisum - isum * asum) / (n * iisum - isum * isum);

    ldouble c = 0;
    for (int i = 0; i < n; ++i) {
        c += (as[i] - (b + d * i)) * (as[i] - (b + d * i));
    }

    std::cout << std::fixed << std::setprecision(10)
              << b << " " << d << "\n"
              << c << "\n";
}

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

    solve();

    return 0;
}