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 <string.h>

int main(void)
{
    char s[4];
    scanf("%s", s);

    int a=0, b=0;
    if(strncmp(&s[0],"0",1)==0 && strncmp(&s[1],"0",1)!=0) a=1;
    if(strncmp(&s[0],"1",1)==0 && (strncmp(&s[1],"0",1)==0 || strncmp(&s[1],"1",1)==0 || strncmp(&s[1],"2",1)==0)) a=1;

    if(strncmp(&s[2],"0",1)==0 && strncmp(&s[3],"0",1)!=0) b=1;
    if(strncmp(&s[2],"1",1)==0 && (strncmp(&s[3],"0",1)==0 || strncmp(&s[3],"1",1)==0 || strncmp(&s[3],"2",1)==0)) b=1;

    if(a==0 && b==0) printf("NA");
    else if(a==0 && b==1) printf("YYMM");
    else if(a==1 && b==0) printf("MMYY");
    else printf("AMBIGUOUS"); 

    return 0;
}