// Working program using Reader Class 
import java.io.*; 
import java.io.FileInputStream; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.util.*; 

public class Main 
{ 
	static class Reader 
	{ 
		final private int BUFFER_SIZE = 1 << 16; 
		private DataInputStream din; 
		private byte[] buffer; 
		private int bufferPointer, bytesRead; 

		public Reader() 
		{ 
			din = new DataInputStream(System.in); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public Reader(String file_name) throws IOException 
		{ 
			din = new DataInputStream(new FileInputStream(file_name)); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public String readLine() throws IOException 
		{ 
			byte[] buf = new byte[64]; // line length 
			int cnt = 0, c; 
			while ((c = read()) != -1) 
			{ 
				if (c == '\n') 
					break; 
				buf[cnt++] = (byte) c; 
			} 
			return new String(buf, 0, cnt); 
		} 

		public int nextInt() throws IOException 
		{ 
			int ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do
			{ 
				ret = ret * 10 + c - '0'; 
			} while ((c = read()) >= '0' && c <= '9'); 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		public long nextLong() throws IOException 
		{ 
			long ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 
			if (neg) 
				return -ret; 
			return ret; 
		} 

		public double nextDouble() throws IOException 
		{ 
			double ret = 0, div = 1; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 

			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 

			if (c == '.') 
			{ 
				while ((c = read()) >= '0' && c <= '9') 
				{ 
					ret += (c - '0') / (div *= 10); 
				} 
			} 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		private void fillBuffer() throws IOException 
		{ 
			bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
			if (bytesRead == -1) 
				buffer[0] = -1; 
		} 

		private byte read() throws IOException 
		{ 
			if (bufferPointer == bytesRead) 
				fillBuffer(); 
			return buffer[bufferPointer++]; 
		} 

		public void close() throws IOException 
		{ 
			if (din == null) 
				return; 
			din.close(); 
		} 
	} 
	 
	public static int gcd(int a, int b) 
    { 
        // Everything divides 0  
        if (a == 0 || b == 0) 
           return 0; 
       
        // base case 
        if (a == b) 
            return a; 
       
        // a is greater 
        if (a > b) 
            return gcd(a-b, b); 
        return gcd(a, b-a); 
    } 

	public static void main(String[] args) throws IOException 
	{ 
		//Reader scan=new Reader(); 
		Scanner scan=new Scanner(System.in);
		PrintWriter out=new PrintWriter(System.out);
		String s=scan.next();
		String s1=s.substring(0, 2);
		String s2=s.substring(2,4);
		int first=Integer.parseInt(s1);
		int second=Integer.parseInt(s2);
		if(first>=1 && first<=12) {
			if(second>=1 && second<=12) {
				out.print("AMBIGUOUS");
			}
			else {
				out.print("MMYY");
			}
		}
		else {
			if(second>=1 && second<=12) {
				out.print("YYMM");
			}
			else {
				out.print("NA");
			}
		}
		//out.print(s1+" "+s2);
		out.close();
	} 
}  import java.io.*; io.* java import java.io.FileInputStream; FileInputStream java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.*; util.* java public class Main 
{ 
	static class Reader 
	{ 
		final private int BUFFER_SIZE = 1 << 16; 
		private DataInputStream din; 
		private byte[] buffer; 
		private int bufferPointer, bytesRead; 

		public Reader() 
		{ 
			din = new DataInputStream(System.in); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public Reader(String file_name) throws IOException 
		{ 
			din = new DataInputStream(new FileInputStream(file_name)); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public String readLine() throws IOException 
		{ 
			byte[] buf = new byte[64]; // line length 
			int cnt = 0, c; 
			while ((c = read()) != -1) 
			{ 
				if (c == '\n') 
					break; 
				buf[cnt++] = (byte) c; 
			} 
			return new String(buf, 0, cnt); 
		} 

		public int nextInt() throws IOException 
		{ 
			int ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do
			{ 
				ret = ret * 10 + c - '0'; 
			} while ((c = read()) >= '0' && c <= '9'); 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		public long nextLong() throws IOException 
		{ 
			long ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 
			if (neg) 
				return -ret; 
			return ret; 
		} 

		public double nextDouble() throws IOException 
		{ 
			double ret = 0, div = 1; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 

			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 

			if (c == '.') 
			{ 
				while ((c = read()) >= '0' && c <= '9') 
				{ 
					ret += (c - '0') / (div *= 10); 
				} 
			} 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		private void fillBuffer() throws IOException 
		{ 
			bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
			if (bytesRead == -1) 
				buffer[0] = -1; 
		} 

		private byte read() throws IOException 
		{ 
			if (bufferPointer == bytesRead) 
				fillBuffer(); 
			return buffer[bufferPointer++]; 
		} 

		public void close() throws IOException 
		{ 
			if (din == null) 
				return; 
			din.close(); 
		} 
	} 
	 
	public static int gcd(int a, int b) 
    { 
        // Everything divides 0  
        if (a == 0 || b == 0) 
           return 0; 
       
        // base case 
        if (a == b) 
            return a; 
       
        // a is greater 
        if (a > b) 
            return gcd(a-b, b); 
        return gcd(a, b-a); 
    } 

	public static void main(String[] args) throws IOException 
	{ 
		//Reader scan=new Reader(); 
		Scanner scan=new Scanner(System.in);
		PrintWriter out=new PrintWriter(System.out);
		String s=scan.next();
		String s1=s.substring(0, 2);
		String s2=s.substring(2,4);
		int first=Integer.parseInt(s1);
		int second=Integer.parseInt(s2);
		if(first>=1 && first<=12) {
			if(second>=1 && second<=12) {
				out.print("AMBIGUOUS");
			}
			else {
				out.print("MMYY");
			}
		}
		else {
			if(second>=1 && second<=12) {
				out.print("YYMM");
			}
			else {
				out.print("NA");
			}
		}
		//out.print(s1+" "+s2);
		out.close();
	} 
} Main public static int gcd(int a, int b) 
    { 
        // Everything divides 0  
        if (a == 0 || b == 0) 
           return 0; 
       
        // base case 
        if (a == b) 
            return a; 
       
        // a is greater 
        if (a > b) 
            return gcd(a-b, b); 
        return gcd(a, b-a); 
    } gcd { 
        // Everything divides 0  
        if (a == 0 || b == 0) 
           return 0; 
       
        // base case 
        if (a == b) 
            return a; 
       
        // a is greater 
        if (a > b) 
            return gcd(a-b, b); 
        return gcd(a, b-a); 
    } if (a == 0 || b == 0) 
           return 0; a == 0 || b == 0 a == 0 a 0 b == 0 b 0 return 0; 0 if (a == b) 
            return a; a == b a b return a; a if (a > b) 
            return gcd(a-b, b); a > b a b return gcd(a-b, b); gcd(a-b, b) gcd a-b a b b return gcd(a, b-a); gcd(a, b-a) gcd a b-a b a int a a int b b public static void main(String[] args) throws IOException 
	{ 
		//Reader scan=new Reader(); 
		Scanner scan=new Scanner(System.in);
		PrintWriter out=new PrintWriter(System.out);
		String s=scan.next();
		String s1=s.substring(0, 2);
		String s2=s.substring(2,4);
		int first=Integer.parseInt(s1);
		int second=Integer.parseInt(s2);
		if(first>=1 && first<=12) {
			if(second>=1 && second<=12) {
				out.print("AMBIGUOUS");
			}
			else {
				out.print("MMYY");
			}
		}
		else {
			if(second>=1 && second<=12) {
				out.print("YYMM");
			}
			else {
				out.print("NA");
			}
		}
		//out.print(s1+" "+s2);
		out.close();
	} main { 
		//Reader scan=new Reader(); 
		Scanner scan=new Scanner(System.in);
		PrintWriter out=new PrintWriter(System.out);
		String s=scan.next();
		String s1=s.substring(0, 2);
		String s2=s.substring(2,4);
		int first=Integer.parseInt(s1);
		int second=Integer.parseInt(s2);
		if(first>=1 && first<=12) {
			if(second>=1 && second<=12) {
				out.print("AMBIGUOUS");
			}
			else {
				out.print("MMYY");
			}
		}
		else {
			if(second>=1 && second<=12) {
				out.print("YYMM");
			}
			else {
				out.print("NA");
			}
		}
		//out.print(s1+" "+s2);
		out.close();
	} Scanner scan=new Scanner(System.in); scan new Scanner(System.in) PrintWriter out=new PrintWriter(System.out); out new PrintWriter(System.out) String s=scan.next(); s scan.next() scan.next scan String s1=s.substring(0, 2); s1 s.substring(0, 2) s.substring s 0 2 String s2=s.substring(2,4); s2 s.substring(2,4) s.substring s 2 4 int first=Integer.parseInt(s1); first Integer.parseInt(s1) Integer.parseInt Integer s1 int second=Integer.parseInt(s2); second Integer.parseInt(s2) Integer.parseInt Integer s2 if(first>=1 && first<=12) {
			if(second>=1 && second<=12) {
				out.print("AMBIGUOUS");
			}
			else {
				out.print("MMYY");
			}
		}
		else {
			if(second>=1 && second<=12) {
				out.print("YYMM");
			}
			else {
				out.print("NA");
			}
		} first>=1 && first<=12 first>=1 first 1 first<=12 first 12 {
			if(second>=1 && second<=12) {
				out.print("AMBIGUOUS");
			}
			else {
				out.print("MMYY");
			}
		} if(second>=1 && second<=12) {
				out.print("AMBIGUOUS");
			}
			else {
				out.print("MMYY");
			} second>=1 && second<=12 second>=1 second 1 second<=12 second 12 {
				out.print("AMBIGUOUS");
			} out.print("AMBIGUOUS") out.print out "AMBIGUOUS" {
				out.print("MMYY");
			} out.print("MMYY") out.print out "MMYY" {
			if(second>=1 && second<=12) {
				out.print("YYMM");
			}
			else {
				out.print("NA");
			}
		} if(second>=1 && second<=12) {
				out.print("YYMM");
			}
			else {
				out.print("NA");
			} second>=1 && second<=12 second>=1 second 1 second<=12 second 12 {
				out.print("YYMM");
			} out.print("YYMM") out.print out "YYMM" {
				out.print("NA");
			} out.print("NA") out.print out "NA" out.close() out.close out String[] args args static class Reader 
	{ 
		final private int BUFFER_SIZE = 1 << 16; 
		private DataInputStream din; 
		private byte[] buffer; 
		private int bufferPointer, bytesRead; 

		public Reader() 
		{ 
			din = new DataInputStream(System.in); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public Reader(String file_name) throws IOException 
		{ 
			din = new DataInputStream(new FileInputStream(file_name)); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public String readLine() throws IOException 
		{ 
			byte[] buf = new byte[64]; // line length 
			int cnt = 0, c; 
			while ((c = read()) != -1) 
			{ 
				if (c == '\n') 
					break; 
				buf[cnt++] = (byte) c; 
			} 
			return new String(buf, 0, cnt); 
		} 

		public int nextInt() throws IOException 
		{ 
			int ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do
			{ 
				ret = ret * 10 + c - '0'; 
			} while ((c = read()) >= '0' && c <= '9'); 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		public long nextLong() throws IOException 
		{ 
			long ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 
			if (neg) 
				return -ret; 
			return ret; 
		} 

		public double nextDouble() throws IOException 
		{ 
			double ret = 0, div = 1; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 

			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 

			if (c == '.') 
			{ 
				while ((c = read()) >= '0' && c <= '9') 
				{ 
					ret += (c - '0') / (div *= 10); 
				} 
			} 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		private void fillBuffer() throws IOException 
		{ 
			bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
			if (bytesRead == -1) 
				buffer[0] = -1; 
		} 

		private byte read() throws IOException 
		{ 
			if (bufferPointer == bytesRead) 
				fillBuffer(); 
			return buffer[bufferPointer++]; 
		} 

		public void close() throws IOException 
		{ 
			if (din == null) 
				return; 
			din.close(); 
		} 
	} Reader final private int BUFFER_SIZE = 1 << 16; BUFFER_SIZE 1 << 16 1 16 private DataInputStream din; din private byte[] buffer; buffer private int bufferPointer bufferPointer bytesRead; bytesRead public Reader() 
		{ 
			din = new DataInputStream(System.in); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} Reader { 
			din = new DataInputStream(System.in); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} din = new DataInputStream(System.in) din new DataInputStream(System.in) buffer = new byte[BUFFER_SIZE] buffer new byte[BUFFER_SIZE] BUFFER_SIZE bufferPointer = bytesRead = 0 bufferPointer bytesRead = 0 bytesRead 0 public Reader(String file_name) throws IOException 
		{ 
			din = new DataInputStream(new FileInputStream(file_name)); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} Reader { 
			din = new DataInputStream(new FileInputStream(file_name)); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} din = new DataInputStream(new FileInputStream(file_name)) din new DataInputStream(new FileInputStream(file_name)) buffer = new byte[BUFFER_SIZE] buffer new byte[BUFFER_SIZE] BUFFER_SIZE bufferPointer = bytesRead = 0 bufferPointer bytesRead = 0 bytesRead 0 String file_name file_name public String readLine() throws IOException 
		{ 
			byte[] buf = new byte[64]; // line length 
			int cnt = 0, c; 
			while ((c = read()) != -1) 
			{ 
				if (c == '\n') 
					break; 
				buf[cnt++] = (byte) c; 
			} 
			return new String(buf, 0, cnt); 
		} readLine { 
			byte[] buf = new byte[64]; // line length 
			int cnt = 0, c; 
			while ((c = read()) != -1) 
			{ 
				if (c == '\n') 
					break; 
				buf[cnt++] = (byte) c; 
			} 
			return new String(buf, 0, cnt); 
		} byte[] buf = new byte[64]; buf new byte[64] 64 int cnt = 0 cnt 0 c; c while ((c = read()) != -1) 
			{ 
				if (c == '\n') 
					break; 
				buf[cnt++] = (byte) c; 
			} (c = read()) != -1 (c = read()) c read() read -1 1 { 
				if (c == '\n') 
					break; 
				buf[cnt++] = (byte) c; 
			} if (c == '\n') 
					break; c == '\n' c '\n' break; buf[cnt++] = (byte) c buf[cnt++] buf cnt++ cnt (byte) c return new String(buf, 0, cnt); new String(buf, 0, cnt) public int nextInt() throws IOException 
		{ 
			int ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do
			{ 
				ret = ret * 10 + c - '0'; 
			} while ((c = read()) >= '0' && c <= '9'); 

			if (neg) 
				return -ret; 
			return ret; 
		} nextInt { 
			int ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do
			{ 
				ret = ret * 10 + c - '0'; 
			} while ((c = read()) >= '0' && c <= '9'); 

			if (neg) 
				return -ret; 
			return ret; 
		} int ret = 0; ret 0 byte c = read(); c read() read while (c <= ' ') 
				c = read(); c <= ' ' c ' ' c = read() c read() read boolean neg = (c == '-'); neg (c == '-') c '-' if (neg) 
				c = read(); neg c = read() c read() read do
			{ 
				ret = ret * 10 + c - '0'; 
			} while ((c = read()) >= '0' && c <= '9'); (c = read()) >= '0' && c <= '9' (c = read()) >= '0' (c = read()) c read() read '0' c <= '9' c '9' { 
				ret = ret * 10 + c - '0'; 
			} ret = ret * 10 + c - '0' ret ret * 10 + c - '0' ret * 10 + c ret * 10 ret 10 c '0' if (neg) 
				return -ret; neg return -ret; -ret ret return ret; ret public long nextLong() throws IOException 
		{ 
			long ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 
			if (neg) 
				return -ret; 
			return ret; 
		} nextLong { 
			long ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 
			if (neg) 
				return -ret; 
			return ret; 
		} long ret = 0; ret 0 byte c = read(); c read() read while (c <= ' ') 
				c = read(); c <= ' ' c ' ' c = read() c read() read boolean neg = (c == '-'); neg (c == '-') c '-' if (neg) 
				c = read(); neg c = read() c read() read do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); (c = read()) >= '0' && c <= '9' (c = read()) >= '0' (c = read()) c read() read '0' c <= '9' c '9' { 
				ret = ret * 10 + c - '0'; 
			} ret = ret * 10 + c - '0' ret ret * 10 + c - '0' ret * 10 + c ret * 10 ret 10 c '0' if (neg) 
				return -ret; neg return -ret; -ret ret return ret; ret public double nextDouble() throws IOException 
		{ 
			double ret = 0, div = 1; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 

			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 

			if (c == '.') 
			{ 
				while ((c = read()) >= '0' && c <= '9') 
				{ 
					ret += (c - '0') / (div *= 10); 
				} 
			} 

			if (neg) 
				return -ret; 
			return ret; 
		} nextDouble { 
			double ret = 0, div = 1; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 

			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 

			if (c == '.') 
			{ 
				while ((c = read()) >= '0' && c <= '9') 
				{ 
					ret += (c - '0') / (div *= 10); 
				} 
			} 

			if (neg) 
				return -ret; 
			return ret; 
		} double ret = 0 ret 0 div = 1; div 1 byte c = read(); c read() read while (c <= ' ') 
				c = read(); c <= ' ' c ' ' c = read() c read() read boolean neg = (c == '-'); neg (c == '-') c '-' if (neg) 
				c = read(); neg c = read() c read() read do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); (c = read()) >= '0' && c <= '9' (c = read()) >= '0' (c = read()) c read() read '0' c <= '9' c '9' { 
				ret = ret * 10 + c - '0'; 
			} ret = ret * 10 + c - '0' ret ret * 10 + c - '0' ret * 10 + c ret * 10 ret 10 c '0' if (c == '.') 
			{ 
				while ((c = read()) >= '0' && c <= '9') 
				{ 
					ret += (c - '0') / (div *= 10); 
				} 
			} c == '.' c '.' { 
				while ((c = read()) >= '0' && c <= '9') 
				{ 
					ret += (c - '0') / (div *= 10); 
				} 
			} while ((c = read()) >= '0' && c <= '9') 
				{ 
					ret += (c - '0') / (div *= 10); 
				} (c = read()) >= '0' && c <= '9' (c = read()) >= '0' (c = read()) c read() read '0' c <= '9' c '9' { 
					ret += (c - '0') / (div *= 10); 
				} ret += (c - '0') / (div *= 10) ret (c - '0') / (div *= 10) (c - '0') c '0' (div *= 10) div 10 if (neg) 
				return -ret; neg return -ret; -ret ret return ret; ret private void fillBuffer() throws IOException 
		{ 
			bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
			if (bytesRead == -1) 
				buffer[0] = -1; 
		} fillBuffer { 
			bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
			if (bytesRead == -1) 
				buffer[0] = -1; 
		} bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE) bytesRead din.read(buffer, bufferPointer = 0, BUFFER_SIZE) din.read din buffer bufferPointer = 0 bufferPointer 0 BUFFER_SIZE if (bytesRead == -1) 
				buffer[0] = -1; bytesRead == -1 bytesRead -1 1 buffer[0] = -1 buffer[0] buffer 0 -1 1 private byte read() throws IOException 
		{ 
			if (bufferPointer == bytesRead) 
				fillBuffer(); 
			return buffer[bufferPointer++]; 
		} read { 
			if (bufferPointer == bytesRead) 
				fillBuffer(); 
			return buffer[bufferPointer++]; 
		} if (bufferPointer == bytesRead) 
				fillBuffer(); bufferPointer == bytesRead bufferPointer bytesRead fillBuffer() fillBuffer return buffer[bufferPointer++]; buffer[bufferPointer++] buffer bufferPointer++ bufferPointer public void close() throws IOException 
		{ 
			if (din == null) 
				return; 
			din.close(); 
		} close { 
			if (din == null) 
				return; 
			din.close(); 
		} if (din == null) 
				return; din == null din null return; din.close() din.close din public class Main 
{ 
	static class Reader 
	{ 
		final private int BUFFER_SIZE = 1 << 16; 
		private DataInputStream din; 
		private byte[] buffer; 
		private int bufferPointer, bytesRead; 

		public Reader() 
		{ 
			din = new DataInputStream(System.in); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public Reader(String file_name) throws IOException 
		{ 
			din = new DataInputStream(new FileInputStream(file_name)); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public String readLine() throws IOException 
		{ 
			byte[] buf = new byte[64]; // line length 
			int cnt = 0, c; 
			while ((c = read()) != -1) 
			{ 
				if (c == '\n') 
					break; 
				buf[cnt++] = (byte) c; 
			} 
			return new String(buf, 0, cnt); 
		} 

		public int nextInt() throws IOException 
		{ 
			int ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do
			{ 
				ret = ret * 10 + c - '0'; 
			} while ((c = read()) >= '0' && c <= '9'); 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		public long nextLong() throws IOException 
		{ 
			long ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 
			if (neg) 
				return -ret; 
			return ret; 
		} 

		public double nextDouble() throws IOException 
		{ 
			double ret = 0, div = 1; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 

			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 

			if (c == '.') 
			{ 
				while ((c = read()) >= '0' && c <= '9') 
				{ 
					ret += (c - '0') / (div *= 10); 
				} 
			} 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		private void fillBuffer() throws IOException 
		{ 
			bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
			if (bytesRead == -1) 
				buffer[0] = -1; 
		} 

		private byte read() throws IOException 
		{ 
			if (bufferPointer == bytesRead) 
				fillBuffer(); 
			return buffer[bufferPointer++]; 
		} 

		public void close() throws IOException 
		{ 
			if (din == null) 
				return; 
			din.close(); 
		} 
	} 
	 
	public static int gcd(int a, int b) 
    { 
        // Everything divides 0  
        if (a == 0 || b == 0) 
           return 0; 
       
        // base case 
        if (a == b) 
            return a; 
       
        // a is greater 
        if (a > b) 
            return gcd(a-b, b); 
        return gcd(a, b-a); 
    } 

	public static void main(String[] args) throws IOException 
	{ 
		//Reader scan=new Reader(); 
		Scanner scan=new Scanner(System.in);
		PrintWriter out=new PrintWriter(System.out);
		String s=scan.next();
		String s1=s.substring(0, 2);
		String s2=s.substring(2,4);
		int first=Integer.parseInt(s1);
		int second=Integer.parseInt(s2);
		if(first>=1 && first<=12) {
			if(second>=1 && second<=12) {
				out.print("AMBIGUOUS");
			}
			else {
				out.print("MMYY");
			}
		}
		else {
			if(second>=1 && second<=12) {
				out.print("YYMM");
			}
			else {
				out.print("NA");
			}
		}
		//out.print(s1+" "+s2);
		out.close();
	} 
} public class Main 
{ 
	static class Reader 
	{ 
		final private int BUFFER_SIZE = 1 << 16; 
		private DataInputStream din; 
		private byte[] buffer; 
		private int bufferPointer, bytesRead; 

		public Reader() 
		{ 
			din = new DataInputStream(System.in); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public Reader(String file_name) throws IOException 
		{ 
			din = new DataInputStream(new FileInputStream(file_name)); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public String readLine() throws IOException 
		{ 
			byte[] buf = new byte[64]; // line length 
			int cnt = 0, c; 
			while ((c = read()) != -1) 
			{ 
				if (c == '\n') 
					break; 
				buf[cnt++] = (byte) c; 
			} 
			return new String(buf, 0, cnt); 
		} 

		public int nextInt() throws IOException 
		{ 
			int ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do
			{ 
				ret = ret * 10 + c - '0'; 
			} while ((c = read()) >= '0' && c <= '9'); 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		public long nextLong() throws IOException 
		{ 
			long ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 
			if (neg) 
				return -ret; 
			return ret; 
		} 

		public double nextDouble() throws IOException 
		{ 
			double ret = 0, div = 1; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 

			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 

			if (c == '.') 
			{ 
				while ((c = read()) >= '0' && c <= '9') 
				{ 
					ret += (c - '0') / (div *= 10); 
				} 
			} 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		private void fillBuffer() throws IOException 
		{ 
			bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
			if (bytesRead == -1) 
				buffer[0] = -1; 
		} 

		private byte read() throws IOException 
		{ 
			if (bufferPointer == bytesRead) 
				fillBuffer(); 
			return buffer[bufferPointer++]; 
		} 

		public void close() throws IOException 
		{ 
			if (din == null) 
				return; 
			din.close(); 
		} 
	} 
	 
	public static int gcd(int a, int b) 
    { 
        // Everything divides 0  
        if (a == 0 || b == 0) 
           return 0; 
       
        // base case 
        if (a == b) 
            return a; 
       
        // a is greater 
        if (a > b) 
            return gcd(a-b, b); 
        return gcd(a, b-a); 
    } 

	public static void main(String[] args) throws IOException 
	{ 
		//Reader scan=new Reader(); 
		Scanner scan=new Scanner(System.in);
		PrintWriter out=new PrintWriter(System.out);
		String s=scan.next();
		String s1=s.substring(0, 2);
		String s2=s.substring(2,4);
		int first=Integer.parseInt(s1);
		int second=Integer.parseInt(s2);
		if(first>=1 && first<=12) {
			if(second>=1 && second<=12) {
				out.print("AMBIGUOUS");
			}
			else {
				out.print("MMYY");
			}
		}
		else {
			if(second>=1 && second<=12) {
				out.print("YYMM");
			}
			else {
				out.print("NA");
			}
		}
		//out.print(s1+" "+s2);
		out.close();
	} 
} Main
// Working program using Reader Class 
import java.io.*; 
import java.io.FileInputStream; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.util.*; 

public class Main 
{ 
	static class Reader 
	{ 
		final private int BUFFER_SIZE = 1 << 16; 
		private DataInputStream din; 
		private byte[] buffer; 
		private int bufferPointer, bytesRead; 

		public Reader() 
		{ 
			din = new DataInputStream(System.in); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public Reader(String file_name) throws IOException 
		{ 
			din = new DataInputStream(new FileInputStream(file_name)); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public String readLine() throws IOException 
		{ 
			byte[] buf = new byte[64]; // line length 
			int cnt = 0, c; 
			while ((c = read()) != -1) 
			{ 
				if (c == '\n') 
					break; 
				buf[cnt++] = (byte) c; 
			} 
			return new String(buf, 0, cnt); 
		} 

		public int nextInt() throws IOException 
		{ 
			int ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do
			{ 
				ret = ret * 10 + c - '0'; 
			} while ((c = read()) >= '0' && c <= '9'); 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		public long nextLong() throws IOException 
		{ 
			long ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 
			if (neg) 
				return -ret; 
			return ret; 
		} 

		public double nextDouble() throws IOException 
		{ 
			double ret = 0, div = 1; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 

			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 

			if (c == '.') 
			{ 
				while ((c = read()) >= '0' && c <= '9') 
				{ 
					ret += (c - '0') / (div *= 10); 
				} 
			} 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		private void fillBuffer() throws IOException 
		{ 
			bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
			if (bytesRead == -1) 
				buffer[0] = -1; 
		} 

		private byte read() throws IOException 
		{ 
			if (bufferPointer == bytesRead) 
				fillBuffer(); 
			return buffer[bufferPointer++]; 
		} 

		public void close() throws IOException 
		{ 
			if (din == null) 
				return; 
			din.close(); 
		} 
	} 
	 
	public static int gcd(int a, int b) 
    { 
        // Everything divides 0  
        if (a == 0 || b == 0) 
           return 0; 
       
        // base case 
        if (a == b) 
            return a; 
       
        // a is greater 
        if (a > b) 
            return gcd(a-b, b); 
        return gcd(a, b-a); 
    } 

	public static void main(String[] args) throws IOException 
	{ 
		//Reader scan=new Reader(); 
		Scanner scan=new Scanner(System.in);
		PrintWriter out=new PrintWriter(System.out);
		String s=scan.next();
		String s1=s.substring(0, 2);
		String s2=s.substring(2,4);
		int first=Integer.parseInt(s1);
		int second=Integer.parseInt(s2);
		if(first>=1 && first<=12) {
			if(second>=1 && second<=12) {
				out.print("AMBIGUOUS");
			}
			else {
				out.print("MMYY");
			}
		}
		else {
			if(second>=1 && second<=12) {
				out.print("YYMM");
			}
			else {
				out.print("NA");
			}
		}
		//out.print(s1+" "+s2);
		out.close();
	} 
} 