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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <string.h>
using namespace std;
int main() {
    string s;
    getline(cin,s);
    int front = 0;
    int back = 0;
    front = stoi(s.substr(0,2));
    back = stoi(s.substr(2,4));
    if (0 < front && front < 13) {
      if (0 < back && back < 13) {
        cout << "AMBIGUOUS";
      } else if (back < 100 || back == 0) {
        cout << "MMYY";
      } else {
        cout << "NA";
      }
    } else if (front < 100 || front == 0) {
      if (0 < back && back < 13) {
        cout << "YYMM";
      } else {
        cout << "NA";
      }  
    } else {
      cout << "NA";
    }
  return 0;
}