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: Wrong Answer)

def solve(inp)
    return inp
end

inp = gets.chomp
left = (inp[0] + inp[1]).to_i
right = (inp[2] + inp[3]).to_i

l_yy = false
l_mm = false
r_yy = false
r_mm = false
na = false

if left > 12
    l_yy = true
    l_mm = false
end
if right > 12
    r_yy = true
    r_mm = false
end

if 0 < left && left <= 12 
    l_yy = true
    l_mm = true
end

if 0 < right && right <= 12 
    r_yy = true
    r_mm = true
end

if left <= 0 || right <= 0
    na = true 
end


if na
    puts "NA"
else
    if l_yy == true
        if l_mm == false && r_yy == true && r_mm == false # YYYY
            puts "NA"
        elsif l_mm == false && r_mm == true # YYMM
            puts "YYMM"
        elsif l_mm == true && r_mm == true && r_yy == true
            puts "AMBIGUOUS"
        end
    elsif r_yy == true
        if l_yy == true && r_mm == false && l_mm == false # YYYY
            puts "NA"
        elsif r_mm == false && l_mm == true # MMYY
            puts "MMYY"
        end
    end
end