
void main()
{
	int i,j,num;
	double mid,max=0;
	float point[100][2];

	scanf("%d",&num);

	for(i=0;i<num;i++)
	{
		scanf("%f %f",&point[i][0],&point[i][1]);
	}
	for(i=0;i<num;i++)
	{
		for(j=i;j<num;j++)
		{
			mid=(point[i][0]-point[j][0])*(point[i][0]-point[j][0])
				+(point[i][1]-point[j][1])*(point[i][1]-point[j][1]);
			if(mid>max)
			{
				max=mid;
			}
		}
	}
	printf("%.4lf\n",sqrt(fabs(max)));
}