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 Go (1.6) (judge verdict: Wrong Answer)

package main

import (
	"fmt"
	"strconv"
)

func main() {
	var S string
	fmt.Scan(&S)
	Fint, _ := strconv.Atoi(S[0:2])
	Sint, _ := strconv.Atoi(S[2:4])
	if Fint == 0 && Sint == 0 {
		fmt.Println("NA")
		return
	}
	if Fint > 12 && Sint > 12 {
		fmt.Println("NA")
		return
	}
	if Fint <= 12 && Sint <= 12 {
		if Fint == 0 {
			fmt.Println("YYMM")
			return
		}
		if Sint == 0 {
			fmt.Println("MMYY")
			return
		}
		fmt.Println("AMBIGUOUS")
	} else if Fint <= 12 && Sint > 12 {
		fmt.Println("MMYY")
	} else if Fint > 12 && Sint <= 12 {
		fmt.Println("YYMM")
	}
}