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 Rust (1.15.1) (judge verdict: Accepted)

#![allow(non_snake_case)]
#![allow(unused_imports)]
macro_rules!input{(source=$s:expr,$($r:tt)*)=>{let mut iter=$s.split_whitespace();let mut next=||{iter.next().unwrap()};input_inner!{next,$($r)*}};($($r:tt)*)=>{let stdin=std::io::stdin();let mut bytes=std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));let mut next=move||->String{bytes.by_ref().map(|r|r.unwrap()as char).skip_while(|c|c.is_whitespace()).take_while(|c|!c.is_whitespace()).collect()};input_inner!{next,$($r)*}};}macro_rules!input_inner{($next:expr)=>{};($next:expr,)=>{};($next:expr,$var:ident:$t:tt$($r:tt)*)=>{let $var=read_value!($next,$t);input_inner!{$next$($r)*}};}macro_rules!read_value{($next:expr,($($t:tt),*))=>{($(read_value!($next,$t)),*)};($next:expr,[$t:tt;$len:expr])=>{(0..$len).map(|_|read_value!($next,$t)).collect::<Vec<_>>()};($next:expr,chars)=>{read_value!($next,String).chars().collect::<Vec<char>>()};($next:expr,usize1)=>{read_value!($next,usize)-1};($next:expr,$t:ty)=>{$next().parse::<$t>().expect("Parseerror")};}

//use proconio::input;
//use proconio::marker::{Bytes, Chars};
use std::cmp::{min, max};
use std::collections::{HashMap, HashSet, VecDeque};
use std::mem::swap;


fn main() {
    input!{
        S: String,
    }
    let ans = solve((S,));
    //println!("{}", ans);
}

fn solve((S,): (String,)) {
    let x = S[..2].parse::<u32>().unwrap();
    let y = S[2..].parse::<u32>().unwrap();
    let a = x < 1 || x > 12;
    let b = y < 1 || y > 12;
    if a && b {
        println!("NA");
    }
    if !a && b {
        println!("MMYY");
    }
    if a && !b {
        println!("YYMM");
    }
    if !a && !b {
        println!("AMBIGUOUS");
    }
}


#[test]
fn test_solve() {
    //let cases = [("CBABA", 29), ("HEART", 55), ("EARTH", 28), ("IOI", 2)];
    //for (i, (S, a)) in cases.iter().enumerate() {
    //    assert_eq!(solve((S.as_bytes().to_vec(),)), *a, "#{}", i);
    //}
}


/*
    Copyright for the `input!` macro at line #3 is held by Hideyuki Tanaka, 2019.  The
    original macro is licensed under BSD 3-clause license.
 
    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are met:
 
    1. Redistributions of source code must retain the above copyright notice, this
    list of conditions and the following disclaimer.
 
    2. Redistributions in binary form must reproduce the above copyright notice,
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.
 
    3. Neither the name of the copyright holder nor the names of its contributors
    may be used to endorse or promote products derived from this software
    without specific prior written permission.
 
    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/