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 (1.42.0) (judge verdict: Accepted)

#[allow(unused_imports)]
use proconio::{fastout, input};

#[fastout]
fn main() {
    input!(s: String);

    let vs: Vec<char> = s.chars().collect();

    let s_f: usize = format!("{}{}", vs[0], vs[1]).parse().unwrap();
    let s_b: usize = format!("{}{}", vs[2], vs[3]).parse().unwrap();

    let is_month_b = !(s_b > 12 || s_b == 0);
    let is_month_f = !(s_f > 12 || s_f == 0);

    let ans = if is_month_b && is_month_f {
        "AMBIGUOUS"
    } else if is_month_b {
        "YYMM"
    } else if is_month_f {
        "MMYY"
    } else {
        "NA"
    };

    println!("{}", ans);
}