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 9.2.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;
int main() 
{
  string s; cin >> s;
  int firstTwo = (((int)s[0] -48) * 10) + (int)(s[1] - 48);
  int lastTwo = (((int)s[2] - 48) * 10) + (int)(s[3] - 48);

  if(firstTwo <= 12 && lastTwo <= 12)
  {
    if(!firstTwo && !lastTwo)
      cout << "NA";
    else 
      cout << "AMBIGUOUS";
  }
  else if(firstTwo>0 && firstTwo <=12)
    cout << "MMYY";
  else if(lastTwo>0 && lastTwo <=12)
    cout << "YYMM";
  else
    cout << "NA";
  cout << endl;
}