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 Fortran (gfortran v4.8.4) (judge verdict: Accepted)

program main
  implicit none
  integer i, mae, ushiro
  character(4) S
  read(*, *) S
  mae = 0
  ushiro = 0
  if (S(1:1) == '0') then
    if (S(2:2) /= '0') then
      mae = 1
    endif
  else if (S(1:1) == '1') then
    if (S(2:2) == '0' .or. S(2:2) == '1' .or. S(2:2) == '2') then
      mae = 1
    endif
  end if
  
  if (S(3:3) == '0') then
    if (S(4:4) /= '0') then
      ushiro = 1
    endif
  else if (S(3:3) == '1') then
    if (S(4:4) == '0' .or. S(4:4) == '1' .or. S(4:4) == '2') then
      ushiro = 1
    endif
  end if

   
  if (mae == 1) then
    if (ushiro == 1) then
      write(*,'(A)') 'AMBIGUOUS'
    else
      write(*,'(A)') 'MMYY'
    end if
  else
    if (ushiro == 1) then
      write(*,'(A)') 'YYMM'
    else
      write(*,'(A)') 'NA'
    end if
  end if
          


end program main