n=gets.to_i
data=[]
n.times do
    d=gets.split.map(&:to_i).sort
    data<< d
end

data.sort!{|a, b|a[0]<=>b[0]}
memo=[]
n.times do |i|
    d=data[i]+[0]
    memo.size.times do |j|
        _d=memo[j]
        d[3]=[d[3], _d[3]+1].max if _d[0]<d[0]&&_d[1]<d[1]&&_d[2]<d[2]
    end
    memo<< d
end

a=0
memo.each do |e|
    a=[a, e[3]].max
end

puts a+1