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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

'use strict'
function Main(input) {
	const a = parseInt(input.slice(0,2));
	const b = parseInt(input.slice(2,4));
  	let ans = "";
  	let has_monthpotential_a = false;
    let has_monthpotential_b = false;
  	if(a >= 0 && a <= 12){
    	has_monthpotential_a = true;
    }
    if(b >= 0 && b <= 12){
    	has_monthpotential_b = true;
    }
	if((has_monthpotential_a === true) && (has_monthpotential_b === false)){
	    ans = "YYMM";
    } else if((has_monthpotential_a === false) && (has_monthpotential_b === true)){
      	ans = "MMYY";
    } else if((has_monthpotential_a === true) && (has_monthpotential_b === true)){
        ans = "AMBIGUOUS";
    } else if((has_monthpotential_a === false) && (has_monthpotential_b === false)){
        ans = "NA";
    }
    
    console.log('%s', ans);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));