#include <iostream>

using namespace std;

int main()
{
    int n, x;
    double summ = 0,sum2 = 0;
    double mx = 0,dx = 0;
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        x = rand() % 10;
        cout << " x : " << x;
        summ += x;
        if ( i == n)
        {
            mx += summ / n;

        }
        for (int j = 1; j <= i; j++)
        {
            sum2 += mx * mx - 2*x * mx + x*x;
            if (j == i) {
                dx = sum2 / n;
            }
        }
    }
    cout << "\ndx : " << dx << " mx : " << mx;

}