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)

use std::io;

fn main() {
	let mut buf = String::new();
	io::stdin().read_line(&mut buf).expect("");
	let s = buf.trim();
	let s1 = &s[0..2];
	let s2 = &s[2..4];
	let f1:i32 = s1.to_string().parse().ok().unwrap();
	let f2:i32 = s2.to_string().parse().ok().unwrap();
	if f1 > 12 && f2 > 12 {
		println!("NA");
	}else if f1 == 0 && f2 > 12{
		println!("NA");
	}else if f1 > 12 && f2 == 0{
		println!("NA");
	}else if f1 == 0 && f2 == 0{
		println!("NA");
	}else if f1 == 0 && f2 <= 12{
		println!("YYMM");
	}else if f1 <= 12 && f2 == 0{
		println!("MMYY");
	}else if f1 <= 12 && f2 > 12 {
		println!("MMYY");
	}else if f1 > 12 && f2 <= 12 {
		println!("YYMM");
	}else{
		println!("AMBIGUOUS");
	}
}