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
)
{
    char s[4] = {0};
    scanf("%s", s);

    if ( ((s[0] == '0') && (s[1] != '0')) ||
         ((s[0] == '1') && ((s[1] == '1') || (s[1] == '2'))) )
    {
        if ( ((s[2] == '0') && (s[3] != '0')) ||
             ((s[2] == '1') && ((s[3] == '1') || (s[3] == '2'))) )
        {
            printf("AMBIGUOUS\n");
        }
        else
        {
            printf("MMYY\n");
        }
    }
    else
    {
        if ( ((s[2] == '0') && (s[3] != '0')) ||
             ((s[2] == '1') && ((s[3] == '1') || (s[3] == '2'))) )
        {
            printf("YYMM\n");
        }
        else
        {
            printf("NA\n");
        }
    }

    return 0;
}