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>
int main(void){
    int S[4];
    char T[4];
    int f = 0;
    int f2 = 0;

    for(int i = 0; i < 4; i++){
        T[i] = 0;
    }

    for(int i = 0; i < 4; i++){
        scanf("%c", &T[i]);
    }

    for(int i = 0; i < 4; i++){
        S[i] = T[i]-48;
    }

    if(S[0] == 0){
        if(S[1] == 0){
            f = 1;
        }
    }
    else if(S[0] == 1){
        if(S[1] > 2){
            f = 1;
        }
    }else {
        f = 1;
    }

    if(S[2] == 0){
        if(S[3] == 0){
            f2 = 1;
        }
    }
    else if(S[2] == 1){
        if(S[3] > 2){
            f2 = 1;
        }
    }
    else {
        f2 = 1;
    }

    if(f == 1){
        if(f2 == 1){
            printf("NA\n");
        }else {
            printf("YYMM\n");
        }
    }else {
        if(f2 == 1){
            printf("MMYY\n");
        }else {
            printf("AMBIGUOUS\n");
        }
    }
    return 0;
}