#define _USE_MATH_DEFINES
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <complex>
#include <string>
#include <vector>
#include <array>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
#include <iterator>
#include <memory>
#include <regex>
using namespace std;

int main()
{
    int n;
    cin >> n;
    vector<int> v(n);
    for(int i=0; i<n; ++i)
        cin >> v[i];

    double x = 0.0;
    double x2 = 0.0;
    double y = 0.0;
    double xy = 0.0;
    for(int i=0; i<n; ++i){
        x += i;
        x2 += i * (double)i;
        y += v[i];
        xy += i * (double)v[i];
    }

    double a = (n * xy - x * y) / (n * x2 - x * x);
    double b = (x2 * y - xy * x) / (n * x2 - x * x);
    double diff = 0.0;
    for(int i=0; i<n; ++i)
        diff += pow((a * i + b) - v[i], 2.0);

    cout.setf(ios_base::fixed, ios_base::floatfield);
    cout << setprecision(10) << b << ' ' << a << endl << diff << endl;

    return 0;
}