import java.util.*;
public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    String yymm = sc.next();
    StringBuilder sb = new StringBuilder();
    sb.append(yymm);
    String yy = sb.substring(0,2);
    String mm = sb.substring(2,4);
    boolean isYYMM = false;
    boolean isMMYY = false;
    String answer = "";
    int month = Integer.parseInt(mm);
    int year = Integer.parseInt(yy);
    if(month>=1&&month<=12){
      isYYMM = true;
    }
    if(year>=1&&year<=12){
      isMMYY = true;
    }
    if(!isYYMM&&!isMMYY){
      answer = "NA";
    }else if(isYYMM&&!isMMYY){
      answer = "YYMM";
    }else if(!isYYMM&&isMMYY){
      answer = "MMYY";
    }else{
      answer = "AMBIGUOUS";
    }
    System.out.println(answer);
  }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz