void main()
{
	int n,v,i,j;
	double max=0;
	double x[100],y[100];
	double distance[100];
	scanf("%d",&n);
	for(v=0;v<n;v++)
	{
		scanf("%lf%lf",&x[v],&y[v]);
	} 
	for(i=0;i<n;i++)
	{
		for(j=i+1;j<n;j++)
		{
			distance[j]=sqrt((x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]));
			if(distance[j]>=max)
				max=distance[j];
		}
	}
	printf("%.4f",max);
}	
