int main()
{
    double *x,*y,t;
    int n,i,j;
    scanf("%d",&n);
    x=(double*)(malloc(n*sizeof(int)));
    y=(double*)(malloc(n*sizeof(int)));
    for(i=0;i<n;i++)
    scanf("%lf %lf",&x[i],&y[i]);
    t=pow((x[1]-x[0]),2)+pow((y[1]-y[0]),2);
    for(i=0;i<n-1;i++)
       {
            for(j=i+1;j<n;j++)
              {if(pow((x[j]-x[i]),2)+pow((y[j]-y[i]),2)>t)
                t=pow((x[j]-x[i]),2)+pow((y[j]-y[i]),2);
              }
       }
       printf("%.4f\n",sqrt(t));
  return 0;
}
