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>
#define rep(i,n) for (int i = 0; i < (n); i++)
#define repf(i,a,b) for (int i = (a); i < (b); i++)
#define repi(i,a,b) for (int i = (a); i <= (b); i++)
#define repr(i,a,b) for (int i = (a); i >= (b); i--)
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define debug(x)  cout << #x << " = " << (x) << endl;
#define SORT(x) sort(all(x));
#define RSORT(x) sort(rall(x));
using namespace std;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vd = vector<double>;
using vb = vector<bool>;
using pii = pair<int, int>;
using vc = vector<char>;
using vvc = vector<vc>;
using vs = vector<string>;
using tiii = tuple<int, int, int>;
const ll inf = 1ll<<29;
const ll mod = 1000000007;
const double eps = 1e-9;
const int dx[4] = {1,0,-1,0};
const int dy[4] = {0,1,0,-1};

int main() {
  string S; cin >> S;
  
  string S1 = S.substr(0,2);
  string S2 = S.substr(2);

  bool flag1 = "01"<=S1 && S1<="12";
  bool flag2 = "01"<=S2 && S2<="12";

  if(!flag1 && flag2) cout << "YYMM" << endl;
  if(flag1 && !flag2) cout << "MMYY" << endl;
  if(flag1 && flag2) cout << "AMBIGUOUS" << endl;
  if(!flag1 && !flag2) cout << "NA" << endl;
}