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;

#define what_is(x) cerr << #x << " is " << x << endl;
#define what_is_v(x) cerr << #x << " is "; for(auto&e: (x)) cerr << e << ' '; cerr << '\n'; //vector, set
#define what_is_a(x, n) cerr << #x << " is "; for(int i=0;i<n;i++) cerr << x[i] << ' '; cerr <<  '\n'; //n first element of array
#define IOS ios::sync_with_stdio(false); cin.tie(0);
#define st first
#define nd second
#define cerr_pair(x) '{' << x.st << ", " << x.nd << '}'
#define pwhat_is(x) cerr << #x << " is " << cerr_pair(x) << endl;
#define pwhat_is_v(x) cerr << #x << " is "; for(auto&e: (x)) cerr << cerr_pair(e) << ' '; cerr << '\n'; //vector, set
#define pwhat_is_a(x, n) cerr << #x << " is "; for(int i=0;i<n;i++) cerr << cerr_pair(x[i]) << ' '; cerr <<  '\n'; //n first element of array
#define endl '\n'
// #define int long long

typedef pair<int,int> pii;
const int N = 1e5+5;
const int INF = 1e9;
const int MOD = 1e9+7;

string s;
int fir, last;
bool isMonth(int x){
	return x>=1 && x<=12;
}
int32_t main()
{
	IOS
	//freopen("input.txt", "r", stdin);
	cin >> s;
	fir = 10*(s[0]-'0') + (s[1]-'0');
	last = 10*(s[2]-'0') + (s[3]-'0');
	if (!isMonth(fir) && !isMonth(last)) cout << "NA\n";
	else if (isMonth(fir) && isMonth(last)) cout << "AMBIGUOUS\n";
	else if (isMonth(fir)) cout << "MMYY\n";
	else cout << "YYMM\n";
	return 0;
}