#include <stdio.h>
#include <stdlib.h>
float karekok(float s)
{
    float a=1;
    float b,k;
    while (a!=b)
    {
        b=a;
        k=s/a;
        k=k+a;
        k=k/2;
        a=k;
    }
    return k;
}


int main()
{
    int sizeofarray,i;//m,s ara değer
    float average,m,s,k;
    printf("give me size of array");
    scanf("%d",&sizeofarray);
    int array[sizeofarray];
    printf("give values");
    for (i=0;i<sizeofarray;i++)
    {
        scanf("%d",&array[i]);
        average=average+(float)array[i];
    }
    average=average/(float)sizeofarray;
    for (i=0;i<sizeofarray;i++)
    {
        m=average-(float)array[i];
        if (m<0)
        {
            m=m*(-1);
        }
        m=m*m;
        s=s+m;
        m=0;
    }s=s/(float)sizeofarray;
    s=karekok(s);

    printf("%f",s);


    return 0;
}