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 C (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>

int main(void) {
  int s;
  int f, b;
  int flag_y = 0;
  int flag_m = 0;
  scanf("%d", &s);
  f = s / 100;
  b = s % 100;
  if ( f >= 1 && f <= 12 ) {
    flag_y = 1;
  }
  if ( b >= 1 && b <= 12 ) {
    flag_m = 1;
  }
  if ( flag_y && flag_m ) {
    printf("AMBIGUOUS\n");
  } else if ( flag_m ) {
    printf("YYMM\n");
  } else if ( flag_y ) {
    printf("MMYY\n");
  } else {
    printf("NA\n");
  }
  return 0;
}