a=(1..n=gets.to_i).map{Complex(*gets.split)}
d=(0...n).map{|u|(0...n).map{|v|(a[u]-a[v]).abs}}
$p=*0...n
def r u;u==$p[u]?u:$p[u]=r($p[u])end
n.times{|u|n.times{|v|d[u][v]>10||$p[r v]=r(u)}}
a=1
n.times{|u|n.times{|v|r(u)==r(v)&&a=[a,2+d[u][v]].max}}
p a