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<bits/stdc++.h>
using namespace std;
string s;
bool valid(string a)
{
	int y=atoi(a.substr(0,2).c_str());
	int m=atoi(a.substr(2).c_str());
	if(y<0)
		return false;
	if(m<=0||m>12)
		return false;
	return true;
}
int main()
{
	cin>>s;
	string t=s.substr(2)+s.substr(0,2);
	if(valid(s)&&valid(t))
		cout<<"AMBIGUOUS"<<endl;
	else if(valid(s)&&!valid(t))
		cout<<"YYMM"<<endl;
	else if(valid(t)&&!valid(s))
		cout<<"MMYY"<<endl;
	else
		cout<<"NA"<<endl;
	return 0;
}