#include<iostream>
#include<vector>
#include<algorithm>
#include<functional>
#include<queue>
#include<stack>
#include<set>
#include<climits>
#include<cstdlib>
#include<cmath>
#include<string>
#include<iomanip>

using namespace std;

#define INF 1 << 29
#define LL long long int

LL const MOD = 1000000007;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    double n;
    cin >> n;
    vector<double> a(n);
    for(int i = 0; i < n; i++){
        cin >> a[i];
    }

    double x = 0.0;
    double y = 0.0;
    double xy = 0.0;
    double xx = 0.0;

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

    double first = ((xx*y)-(xy*x))/(((double)n)*xx - (x*x) );
    double d = ((((double)n)*xy)-(x*y))/(((double)n)*xx - (x*x));

    double c = 0.0;

    for(int i = 0; i < n; i++){
        c += (a[i] - (((double)i)*d + first))*(a[i] - (((double)i)*d + first));
    }

    cout << fixed;
    cout << setprecision(17) << first << " ";
    cout << setprecision(17) << d << endl;
    cout << setprecision(17) << c << endl;
    
    return 0;
}