Problem:
Score : 200 points

Problem Statement

You have a digit sequence S of length 4. You are wondering which of the following formats S is in:

YYMM format: the last two digits of the year and the two-digit representation of the month (example: 01 for January), concatenated in this order

MMYY format: the two-digit representation of the month and the last two digits of the year, concatenated in this order

If S is valid in only YYMM format, print YYMM; if S is valid in only MMYY format, print MMYY; if S is valid in both formats, print AMBIGUOUS; if S is valid in neither format, print NA.

Constraints

S is a digit sequence of length 4.

Input

Input is given from Standard Input in the following format:

S

Output

Print the specified string: YYMM, MMYY, AMBIGUOUS or NA.

Sample Input 1

1905

Sample Output 1

YYMM

May XX19 is a valid date, but 19 is not valid as a month. Thus, this string is only valid in YYMM format.

Sample Input 2

0112

Sample Output 2

AMBIGUOUS

Both December XX01 and January XX12 are valid dates. Thus, this string is valid in both formats.

Sample Input 3

1700

Sample Output 3

NA

Neither 0 nor 17 is valid as a month. Thus, this string is valid in neither format.

Solution in JavaScript (node.js v5.12) (judge verdict: Runtime Error)

def resolve():
    S = input()

    # YY: 00<=YY<=99
    # MM: 01<=MM<=12
    
    f_canYY = lambda x: '00' <= x and x <= '99'
    f_canMM = lambda x: '01' <= x and x <= '12'

    a = S[0:2]
    b = S[2:4]

    yymm = f_canYY(a) and f_canMM(b)
    mmyy = f_canMM(a) and f_canYY(b)

    if yymm and mmyy:
        print('AMBIGUOUS')
    elif yymm and not mmyy:
        print('YYMM')
    elif not yymm and mmyy:
        print('MMYY')
    else:
        print('NA')

resolve()