l1 = gets.chomp!
abort 'L1' unless l1=~/^[0-9]+$/
n = l1.to_i
abort 'N' unless 3 <= n
E9 = 1e9.to_i
n.times do
    l = gets.chomp!
    abort 'L' unless l=~/^[-0-9]+ [-0-9]+$/
    x,y = l.split.map(&:to_i)
    abort 'x' unless -E9 <= x && x <= E9
    abort 'y' unless -E9 <= y && y <= E9
    abort 'O' if x == 0 && y == 0
end

puts 'AC'