#include<cstdio>

#include<ctime>

#include<cmath>

#include<cstdlib>

const int N=105;

struct point

{

    double x,y;

}ps[N];

int n;

double t,ans,tans,tx,ty,nx,ny,temp;

inline double get(int x){return 1.0*((rand()%x)*(rand()%x)%x);}

inline double sqr(double x){return x*x;}

inline double dis(double x,double y,point &p)

{

    return sqrt(sqr(x-p.x)+sqr(y-p.y));

}

inline double calc(double x,double y)

{

    double res=0;

    for(register int i=1;i<=n;i++)res+=dis(x,y,ps[i]);

    return res;

}

int main()

{

    scanf("%d",&n);nx=ny=0;t=100000;

    for(register int i=1;i<=n;i++)

    {

        scanf("%lf%lf",&ps[i].x,&ps[i].y);

        nx+=ps[i].x;ny+=ps[i].y;

    }

    nx/=n;ny/=n;tans=ans=calc(nx,ny);

    while(t>0.02)

    {

        tx=ty=0;

        for(register int i=1;i<=n;i++)

        {

            tx+=(ps[i].x-nx)/dis(nx,ny,ps[i]);

            ty+=(ps[i].y-ny)/dis(nx,ny,ps[i]);

        }

        temp=calc(nx+tx*t,ny+ty*t);

        if(temp<ans)

        {

            tans=ans=temp;nx+=tx*t;ny+=ty*t;

        }else if(log((temp-ans)/t)<get(10000)/10000.0)

        {

            ans=temp;nx+=tx*t;ny+=ty*t;

        }

        t*=0.9;

    }

    if(tans<ans)ans=tans;

    printf("%.0lf",ans);

    return 0;

}