S=input()
if 1 <= int(S[0:2]) <= 12:
  if 1 <= int(S[2:4]) <= 12:
    print("AMBIGUOUS")
  else:
    print("MMYY")
else:
  if 1 <= int(S[2:4]) <= 12:
    print("YYMM")
  else:
    print("NA") S=input() S input() input if 1 <= int(S[0:2]) <= 12:
  if 1 <= int(S[2:4]) <= 12:
    print("AMBIGUOUS")
  else:
    print("MMYY")
else:
  if 1 <= int(S[2:4]) <= 12:
    print("YYMM")
  else:
    print("NA") 1 <= int(S[0:2]) <= 12 1 <= int(S[0:2]) 1 int(S[0:2]) int S[0:2] S 0:2 0 2 12 if 1 <= int(S[2:4]) <= 12:
    print("AMBIGUOUS")
  else:
    print("MMYY") 1 <= int(S[2:4]) <= 12 1 <= int(S[2:4]) 1 int(S[2:4]) int S[2:4] S 2:4 2 4 12 print("AMBIGUOUS") print "AMBIGUOUS" print("MMYY") print "MMYY" if 1 <= int(S[2:4]) <= 12:
    print("YYMM")
  else:
    print("NA") 1 <= int(S[2:4]) <= 12 1 <= int(S[2:4]) 1 int(S[2:4]) int S[2:4] S 2:4 2 4 12 print("YYMM") print "YYMM" print("NA") print "NA" S=input() input() S
S=input()
if 1 <= int(S[0:2]) <= 12:
  if 1 <= int(S[2:4]) <= 12:
    print("AMBIGUOUS")
  else:
    print("MMYY")
else:
  if 1 <= int(S[2:4]) <= 12:
    print("YYMM")
  else:
    print("NA")