#include <iostream>
#include <random>
#include <bits/stdc++.h>
using namespace std;
using ull = __int128;
using ll = long long;
#define rep(i,a,b) for(int i=a;i<b;i++)
#include <iostream>
using namespace std;

const int MAX = 2000010;
const int MOD = 1000000007;

long long fac[MAX], finv[MAX], inv[MAX];

// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}

// 二項係数計算
long long COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

int main() {
 COMinit();
 int q;
 cin>>q;
 vector<ll> y(q);
 vector<ll> x(q);
 for(int i=0;i<q;i++){
     cin>>y.at(i);
     x.at(i)=i+1;
 }
 double a,b,c,d,e,f,g,h;
 a=0;
 b=0;
 c=0;
 d=0;
 e=0;
 f=0;
 g=0;
 h=0;
 for(int i=0;i<q;i++){
     a=a+q*x.at(i)*y.at(i);
     e=e+x.at(i);
     f=f+y.at(i);
     b=b+q*x.at(i)*x.at(i);
     g=g+x.at(i)*x.at(i);
     h=h+x.at(i)*y.at(i);
 }
 c=g*f-h*e;
 a=a-e*f;
  b=b-e*e;
 d=b;
  double ans=0;
  double o=c/d+a/b;
  double k=a/b;
  for(int i=0;i<a;i++){
    ans=ans+(y.at(i)-o)*(y.at(i)-o);
    o=o+k;
  }
 cout << std::fixed << std::setprecision(15) << c/d+a/b <<" ";
  cout << std::fixed << std::setprecision(15) << a/b << endl;
  cout << std::fixed << std::setprecision(15) << ans << endl;
}