int main()
{
	int i,n,t;
	double f=0.0,b[100][100];
	struct S
	{
		double x,y;
		
	}s[1000];
	scanf("%d",&n);
	for (i=0;i<n;i++)
	{
		scanf("%lf%lf",&s[i].x,&s[i].y);
	}
	for (i=0;i<n;i++)
		for(t=0;t<n;t++)
		{
			b[i][t]=sqrt((s[i].x-s[t].x)*(s[i].x-s[t].x)+(s[i].y-s[t].y)*(s[i].y-s[t].y));
			if(b[i][t]>=f)
				f=b[i][t];
		}
	printf("%.4lf",f);


	return 0;
}