require "prime"
n=gets.to_i
a=gets.split.map(&:to_i)
x=0
a.each do |aa|
  next if aa==1
  b=0
  Prime.prime_division(aa).each do |aaa,bbb|
    b+=bbb
  end
  x^=b
end
if x==0
  puts "black"
else
  puts "white"
end