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

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout<<setprecision(std::numeric_limits<float>::max_digits10);
  ll n; cin>>n;
  vector<ll> a(n);
  rep(i,n) cin>>a[i];
  ll C = 0;
  rep(i,n) {
    C+=i*a[i];
  }
  ll D = 0;
  rep(i,n) {
    D += a[i];
  }
  ll B = n*(n-1)/2;
  ll A = n*(n-1)*(2*n-1)/6;
  double b = 1.0*(A*D-B*C)/(n*A-B*B)*1.0;
  double d = (D-n*b)/B;
  double c = 0;
  rep(i,n) {
    double t = (b+i*d-a[i]);
    c += t*t;
  }
  cout << b << " " << d << endl;
  cout << c << endl;
  return 0;
}