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 (Clang 3.8.0) (judge verdict: Accepted)

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[]) {

  char S[5];
  char s1[3], s2[3];

  scanf("%s", S);

  s1[0] = S[0];
  s1[1] = S[1];
  s2[0] = S[2];
  s2[1] = S[3];

  s1[2] = 0;
  s2[2] = 0;

  int a, b;
  a = atoi(s1);
  b = atoi(s2);

  if (a == 0 || a > 12) {
    if (b == 0 || b > 12 ) {
      printf("NA");
    } else {
      printf("YYMM");
    }
  } else {
    if (b == 0 || b > 12 ) {
      printf("MMYY");
    } else {
      printf("AMBIGUOUS");
    }
  }

}