#include <bits/stdc++.h>
using namespace std;

pair<double, double> least_squares(const vector<int> &x, const vector<int> &y) {
  int n = x.size();
  vector<double> xy(n);
  for (int i = 0; i < n; ++i) xy[i] = 1.0 * x[i] * y[i];
  vector<double> x2(n);
  for (int i = 0; i < n; ++i) x2[i] = 1.0 * x[i] * x[i];
  double xsum = accumulate(x.begin(), x.end(), 0.0);
  double ysum = accumulate(y.begin(), y.end(), 0.0);
  double xysum = accumulate(xy.begin(), xy.end(), 0.0);
  double x2sum = accumulate(x2.begin(), x2.end(), 0.0);
  double au = n * xysum - xsum * ysum;
  double av = n * x2sum - xsum * xsum;
  double bu = x2sum * ysum - xysum * xsum;
  double bv = n * x2sum - xsum * xsum;
  return {au / av, bu / bv};
}

signed main() {
  ios::sync_with_stdio(false);

  int N;
  cin >> N;

  vector<int> A(N);
  for (int i = 0; i < N; ++i) cin >> A[i];

  vector<int> X(N);
  iota(X.begin(), X.end(), 0);
  double a, b;
  tie(a, b) = least_squares(X, A);

  vector<double> v(N);
  v[0] = b;
  for (int i = 0; i + 1 < N; ++i) v[i + 1] = v[i] + a;

  double c = 0;
  for (int i = 0; i < N; ++i) {
    double x = v[i] - A[i];
    c += x * x;
  }

  cout << fixed << setprecision(8) << b << ' ' << a << '\n' << ' ' << c << endl;
}