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;
int ans,x,a,f;
int main(){
    cin>>s;
    for(int i=0;i<=1;i++)
    {
    	a=s[i]-48;
    	x=x*10+a;
	}
	if(x<=12&&x>0) ans++,f=1;
	x=0;
	for(int i=2;i<=3;i++)
	{
		a=s[i]-48;
    	x=x*10+a;
	}
	if(x<=12&&x>0) ans++,f=2;
	if(ans==0) cout<<"NA";
	if(ans==2) cout<<"AMBIGUOUS";
	if(ans==1)
	{
		if(f==1) cout<<"MMYY";
		else cout<<"YYMM";
	}
	return 0;
}