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'
function Main(input) {
    input = input.split("\n")[0].split('')
    let fore = input[0] + input[1]
    let back = input[2] + input[3]

    fore = parseInt(fore)
    back = parseInt(back)

    const isYear = (num) => {
      return 0 <= num && num < 100
    }
    const isMonth = (num) => {
       return 0 < num && num < 13 
    }
    
    const isForeYY = isYear(fore)
    const isBackYY = isYear(back)
    const isForeMM = isMonth(fore)
    const isBackMM = isMonth(back)
    
    const isYYMM = isForeYY && isBackMM
    const isMMYY = isForeMM && isBackYY

     let result = ""

    if(isYYMM && isMMYY ){
       result =  'AMBIGUOUS'
    } else if (isYYMM) {
      result =  'YYMM'
    } else if (isMMYY) {
      result = 'MMYY'
    } else {
      result = 'NA'
    }
    


    console.log(result)
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"))