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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php



function checkMonth($n){
    $n = (int)$n;
    if($n > 0 && $n < 13){
        return(true);
    }   else{
        return(false);
    }
}
$n = 0;
# 整数の入力
fscanf(STDIN, "%s", $n);

$array = str_split($n,2);

if(checkMonth($array[0]) && checkMonth($array[1])){
    echo "AMBIGUOUS";
}elseif(checkMonth($array[0])){
    echo "MMYY";
}elseif(checkMonth($array[1])){
    echo "YYMM";
}else{
    echo "NA";
}