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: Accepted)

"use strict";

// read lines from stdin
const input = parseInt(require("fs")
  .readFileSync("/dev/stdin", "utf8"), 10);

const first = Math.floor(input / 100);
const last = input % 100;

function canReadAsMonth(num) {
  return num > 0 && num < 13;
}

if (canReadAsMonth(first) && canReadAsMonth(last)) {
  console.log("AMBIGUOUS");
} else if (!canReadAsMonth(first) && canReadAsMonth(last)) {
  console.log("YYMM");
} else if (canReadAsMonth(first) && !canReadAsMonth(last)) {
  console.log("MMYY");
} else {
  console.log("NA");
}