python s = input().strip() # 拆分前后两位 a = int(s[:2]) b = int(s[2:]) ok_a = 1 <= b <= 12 ok_b = 1 <= a <= 12 if ok_a and ok_b: print("AMBIGUOUS") elif ok_a: print("YYMM") elif ok_b: print("MMYY") else: print("NA")