def out1(n)
  m = n/4
  m.times.map{|i| i *= 4;  [3+i, 1+i, 4+i, 2+i] }.flatten
end

def out3(n)
  out1(n).reverse
end

def out5(n)
  m = n/2
  (1..m).zip((1..m).to_a.reverse).map{|x,y| [x, m+y]}.flatten
end

def out6(n)
  m = n/2
  (1..m).zip(1..m).map{|x,y| [x, m+y]}.flatten
end

def out7(n)
  m = n/2
  (1..m).zip(1..m).map{|x,y| [m+x, y]}.flatten
end

id = ARGV[0] || '1'

n = 200000
aa = send('out' + id, n)
p aa.size
puts aa*' '