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