void main()
{
	int n,i,j;
	double a[1000],b[1000],max=0.0000;
	scanf("%d",&n);
	for(i=0;i<n;i++){
		scanf("%lf %lf\n",&a[i],&b[i]);
	}
    for(i=0;i<n;i++){
		for(j=0;j<n;j++){
		    if(sqrt((a[i]-a[j])*(a[i]-a[j])+(b[i]-b[j])*(b[i]-b[j]))>max){
		    max=sqrt((a[i]-a[j])*(a[i]-a[j])+(b[i]-b[j])*(b[i]-b[j]));
			}
		}
	}
	printf("%.4lf\n",max);
}