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 checkM = (num) => {
      if (1 <= num && num <= 12) {
          return true;
        } else {
            return false;
        }
    };

  const checkY = (num) => {
      if (1 <= num && num <= 99) {
          return true;
        } else {
            return false;
        }
    };

  const args = input.split("\n");
  const S = args[0];

  const first = parseInt(S.slice(0, 2));
  const second = parseInt(S.slice(2,4));

  let firstIsM = checkM(first);
  let firstIsY = checkY(first);

  let secondIsM = checkM(second);
  let secondIsY = checkY(second);

  if((firstIsY && secondIsM) && (firstIsM && secondIsY)) {
      console.log("AMBIGUOUS");
  } else if(firstIsY && secondIsM) {
      console.log("YYMM");
  } else if(firstIsM && secondIsY) {
      console.log('MMYY');
  } else {
      console.log('NA');
  }

}
main(require("fs").readFileSync("/dev/stdin", "utf8"));