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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;
public class Main{
 public static void main(String[] args){
   Scanner sc = new Scanner(System.in);
   String YM = sc.next();
   
   boolean YYMM = false;
   boolean MMYY = false;
   
   
   if(YM.charAt(0)=='0'){
    if(YM.charAt(1)!='0'){
     MMYY = true;
    }
   }
     
   if(YM.charAt(0)=='1'){
    if(YM.charAt(1)=='0' || YM.charAt(1)=='1' || YM.charAt(1)=='2'){
     MMYY = true;
    }     
   }

     
      if(YM.charAt(2)=='0'){
    if(YM.charAt(3)!='0'){
     YYMM = true;
    }
   }
     
   if(YM.charAt(2)=='1'){
    if(YM.charAt(3)=='0' || YM.charAt(3)=='1' || YM.charAt(3)=='2'){
     YYMM = true;
    }     
   }
     if(YYMM && MMYY){
         System.out.println("AMBIGUOUS");
     }
      else if(YYMM && !(MMYY)){
         System.out.println("YYMM");
     }
      else if(!(YYMM) && MMYY){
         System.out.println("MMYY");
     }
      else{
         System.out.println("NA");
     }
   
 }
}