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 Haskell (GHC 7.10.3) (judge verdict: Wrong Answer)

module Main where

import           Control.Monad
import           Data.Array.IO
import           Data.Char
import           Data.List
import           Data.List.Split
import           Data.Ord
import qualified Data.Vector.Unboxed as V
import           Text.Printf

main :: IO ()
main = do
  s <- getLine
  let f = read $ take 2 s :: Int
      t = read $ drop 2 s :: Int
      yymm = f > 0 && f < 99 && t > 0 && t < 13
      mmyy = f > 0 && f < 13 && t > 0 && t < 99
  if yymm && mmyy
    then putStrLn "AMBIGUOUS"
    else if yymm
         then putStrLn "YYMM"
         else if mmyy
              then putStrLn "MMYY"
              else putStrLn "NA"