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

