#!/usr/bin/ruby

DEBUG = false

def debug_print(nonterminal, stack)
  if DEBUG
    puts "matching #{nonterminal}, stack: #{stack.reverse.join(", ")}"
  end
end

def match(expected, stack)
  if stack.pop != expected
    raise "reject"
  end
end

def a(stack)
  debug_print('A', stack)
  match('b', stack)
  b(stack)
end

def b(stack)
  debug_print('B', stack)
  match('a', stack)
  c(stack)
end

def c(stack)
  debug_print('C', stack)
  if !stack.empty?
    match('b', stack)
    b(stack)
  end
end

while line = STDIN.gets
  begin
    # use an array as a stack, with the end of the array acting as the top
    # (beginning of input)
    stack = line.split.reverse
    a(stack)
    if !stack.empty?
      raise 'reject'
    end
    puts 'accept'
  rescue Exception => e
    puts e
  end
end