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>
#include<stdlib.h>
#include<stdint.h>
#include<inttypes.h>
#include<string.h>
#include<math.h>

typedef int32_t i32;
typedef int64_t i64;

#define MAX(a,b) ((a) > (b) ? (a) : (b))
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#define ABS(a) ((a) > (0) ? (a) : -(a))

void run (void) {
  char s[5];
  scanf ("%s", s);
  i32 a = 10 * (s[0] - '0') + s[1] - '0';
  i32 b = 10 * (s[2] - '0') + s[3] - '0';
  if (a == 0) {
    if (1 <= b && b <= 12) {
      puts ("YYMM");
    } else {
      puts ("NA");
    }
  } else if (b == 0) {
    if (1 <= a && a <= 12) {
      puts ("MMYY");
    } else {
      puts ("NA");
    }
  } else {
    if (a <= 12 && b <= 12) {
      puts ("AMBIGUOUS");
    } else if (a > 12 && b > 12) {
      puts ("NA");
    } else {
      puts (a <= 12 ? "MMYY" : "YYMM");
    }
  }
}

int main (void) {
  run();
  return 0;
}