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 PyPy3 (2.4.0) (judge verdict: Accepted)

from itertools import*
from math import*
from collections import*
from heapq import*
from bisect import bisect_left,bisect_right
from copy import deepcopy
inf = 10**18
mod = 10**9+7
from functools import reduce
import sys
sys.setrecursionlimit(10**7)

s = input()
s1 = s[0:2]
s2 = s[2:4]
#どちらかが00になっているとき
if (s1[0]=="0" and s1[1]=="0") or(s2[0]=="0" and s2[1]=="0"):
    if  0<int(s1[0])*10+int(s1[1]) <12:
        print("MMYY")
    elif 0 < int(s2[0])*10+int(s2[1]) <12:
        print("YYMM")
    else:
        print("NA")
else:
    #最初が0Xのとき
    if s1[0]=="0":
        if s2[0]=="0":
            print("AMBIGUOUS")
        else:
            if eval(s2)>12:
                print("MMYY")
            else:
                print("AMBIGUOUS")
    else:
        #最初がYXのかたちY>=1のとき
        if eval(s1)>12:
            if s2[0]=="0" or eval(s2) <= 12:
                print("YYMM")
            else:
                print("NA")
        else:
            if s2[0]=="0":
                print("AMBIGUOUS")
            else:
                if eval(s2)>12:
                    print("MMYY")
                else:
                    print("AMBIGUOUS")