s=input()

if 0<int(s[:2])<=12:
    if 0<int(s[2:])<=12:
        print('AMBIGUOUS')
    else:
        print('MMYY')
else:
    if 0<int(s[2:])<=12:
        print('YYMM')
    else:
        print('NA') s=input() s input() input if 0<int(s[:2])<=12:
    if 0<int(s[2:])<=12:
        print('AMBIGUOUS')
    else:
        print('MMYY')
else:
    if 0<int(s[2:])<=12:
        print('YYMM')
    else:
        print('NA') 0<int(s[:2])<=12 0<int(s[:2]) 0 int(s[:2]) int s[:2] s :2 2 12 if 0<int(s[2:])<=12:
        print('AMBIGUOUS')
    else:
        print('MMYY') 0<int(s[2:])<=12 0<int(s[2:]) 0 int(s[2:]) int s[2:] s 2: 2 12 print('AMBIGUOUS') print 'AMBIGUOUS' print('MMYY') print 'MMYY' if 0<int(s[2:])<=12:
        print('YYMM')
    else:
        print('NA') 0<int(s[2:])<=12 0<int(s[2:]) 0 int(s[2:]) int s[2:] s 2: 2 12 print('YYMM') print 'YYMM' print('NA') print 'NA' s=input() input() s
s=input()

if 0<int(s[:2])<=12:
    if 0<int(s[2:])<=12:
        print('AMBIGUOUS')
    else:
        print('MMYY')
else:
    if 0<int(s[2:])<=12:
        print('YYMM')
    else:
        print('NA')
