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 Ruby (2.3.3) (judge verdict: Accepted)

n = gets.chomp
x = n.chars
for i in 0..x.length-1
    x[i]=x[i].to_i
end
#p x
a = x[0]*10+x[1]
b = x[2]*10+x[3]
#p a
#p b
cnt_a = 0
cnt_b = 0
if a <= 12 && a >= 1
    cnt_a = 1
end
if b <= 12 && b >= 1
    cnt_b = 1
end
#p cnt_a
#p cnt_b
if cnt_a==1&&cnt_b==1
    puts "AMBIGUOUS"
elsif cnt_a==0 &&cnt_b==1
    puts "YYMM"
elsif cnt_a==1&&cnt_b==0
    puts "MMYY"
else
    puts "NA"
end