S=gets.chomp↲
y1=(S[0]+S[1]).to_i↲
y2=(S[2]+S[3]).to_i↲
if y1 != 0 and y1 <=12↲
  if y2 != 0 and y2 <=12↲
    puts "AMBIGUOUS"↲
  else↲
    puts "MMYY"↲
  end↲
else--↲
  if y2 != 0 and y2 <=12↲
    puts "YYMM"↲
  else↲
    puts "NA"↲
  end↲
end↲