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 Python (3.4.3) (judge verdict: Wrong Answer)

import re
s = input()
f = s[:2]
l = s[2:]
year_flg = 0
month_flg = 0
if int(l) == 0:
    print('NA')
    exit()
if re.match('^(0\d|1(0|1|2))$', l):
    if int(l) != 0:
        year_flg = 1
if re.match('^(0\d|1(0|1|2))$', f):
    if int(f) != 0:
        month_flg = 1
if year_flg == 1:
    if month_flg == 1:
        print('AMBIGUOUS')
    else:
        print('YYMM')
elif month_flg == 1:
    print('MMYY')
else:
    print('NA')