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 is_month(int m) {
    return (m >= 1) && (m <= 12);
}

int main () {
    int S;
    scanf("%d", &S);

    int bottom_2 = S % 100;
    int top_2 = S / 100;

    char *ans;
    if (is_month(top_2) && is_month(bottom_2)) {
        ans = "AMBIGUOUS";
    } else if (is_month(top_2) && !is_month(bottom_2)) {
        ans = "MMYY";
    } else if (!is_month(top_2) && is_month(bottom_2)) {
        ans = "YYMM";
    } else {
        ans = "NA";
    }

    printf("%s\n", ans);
    return 0;
}