import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Deque;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.function.BiConsumer;

/**
 * Built using CHelper plug-in Actual solution is at the top
 */

public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		Task solver = new Task();
		solver.solve(1, in, out);
		out.close();
	}

	static class Task {
		public void solve(int testNumber, InputReader in, PrintWriter out) {
			String S = in.next();
			int a = Integer.parseInt(S.substring(0, 2));
			int b = Integer.parseInt(S.substring(2, 4));
			String ans = "NA";
			if ((0 <= a && a <= 99 && 1 <= b && b <= 12) && (1 <= a && a <= 12 && 0 <= b && b <= 99)) {
				ans = "AMBIGUOUS";
			} else if (0 <= a && a <= 99 && 1 <= b && b <= 12) {
				ans = "YYMM";
			} else if (1 <= a && a <= 12 && 0 <= b && b <= 99) {
				ans = "MMYY";
			}
			out.println(ans);
		}
	}

	static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public InputReader(InputStream stream) {
			reader = new BufferedReader(new InputStreamReader(stream), 32768);
			tokenizer = null;
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

		public char nextChar() {
			return next().charAt(0);
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}

		public double nextDouble() {
			return Double.parseDouble(next());
		}

		public long nextLong() {
			return Long.parseLong(next());
		}

	}
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.OutputStream; OutputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.ArrayList; ArrayList java.util import java.util.Arrays; Arrays java.util import java.util.Collections; Collections java.util import java.util.Deque; Deque java.util import java.util.HashSet; HashSet java.util import java.util.Iterator; Iterator java.util import java.util.List; List java.util import java.util.Map; Map java.util import java.util.Queue; Queue java.util import java.util.Set; Set java.util import java.util.StringTokenizer; StringTokenizer java.util import java.util.TreeMap; TreeMap java.util import java.util.function.BiConsumer; BiConsumer java.util.function public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		Task solver = new Task();
		solver.solve(1, in, out);
		out.close();
	}

	static class Task {
		public void solve(int testNumber, InputReader in, PrintWriter out) {
			String S = in.next();
			int a = Integer.parseInt(S.substring(0, 2));
			int b = Integer.parseInt(S.substring(2, 4));
			String ans = "NA";
			if ((0 <= a && a <= 99 && 1 <= b && b <= 12) && (1 <= a && a <= 12 && 0 <= b && b <= 99)) {
				ans = "AMBIGUOUS";
			} else if (0 <= a && a <= 99 && 1 <= b && b <= 12) {
				ans = "YYMM";
			} else if (1 <= a && a <= 12 && 0 <= b && b <= 99) {
				ans = "MMYY";
			}
			out.println(ans);
		}
	}

	static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public InputReader(InputStream stream) {
			reader = new BufferedReader(new InputStreamReader(stream), 32768);
			tokenizer = null;
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

		public char nextChar() {
			return next().charAt(0);
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}

		public double nextDouble() {
			return Double.parseDouble(next());
		}

		public long nextLong() {
			return Long.parseLong(next());
		}

	}
} Main public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		Task solver = new Task();
		solver.solve(1, in, out);
		out.close();
	} main {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		Task solver = new Task();
		solver.solve(1, in, out);
		out.close();
	} InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out InputReader in = new InputReader(inputStream); in new InputReader(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) Task solver = new Task(); solver new Task() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class Task {
		public void solve(int testNumber, InputReader in, PrintWriter out) {
			String S = in.next();
			int a = Integer.parseInt(S.substring(0, 2));
			int b = Integer.parseInt(S.substring(2, 4));
			String ans = "NA";
			if ((0 <= a && a <= 99 && 1 <= b && b <= 12) && (1 <= a && a <= 12 && 0 <= b && b <= 99)) {
				ans = "AMBIGUOUS";
			} else if (0 <= a && a <= 99 && 1 <= b && b <= 12) {
				ans = "YYMM";
			} else if (1 <= a && a <= 12 && 0 <= b && b <= 99) {
				ans = "MMYY";
			}
			out.println(ans);
		}
	} Task public void solve(int testNumber, InputReader in, PrintWriter out) {
			String S = in.next();
			int a = Integer.parseInt(S.substring(0, 2));
			int b = Integer.parseInt(S.substring(2, 4));
			String ans = "NA";
			if ((0 <= a && a <= 99 && 1 <= b && b <= 12) && (1 <= a && a <= 12 && 0 <= b && b <= 99)) {
				ans = "AMBIGUOUS";
			} else if (0 <= a && a <= 99 && 1 <= b && b <= 12) {
				ans = "YYMM";
			} else if (1 <= a && a <= 12 && 0 <= b && b <= 99) {
				ans = "MMYY";
			}
			out.println(ans);
		} solve {
			String S = in.next();
			int a = Integer.parseInt(S.substring(0, 2));
			int b = Integer.parseInt(S.substring(2, 4));
			String ans = "NA";
			if ((0 <= a && a <= 99 && 1 <= b && b <= 12) && (1 <= a && a <= 12 && 0 <= b && b <= 99)) {
				ans = "AMBIGUOUS";
			} else if (0 <= a && a <= 99 && 1 <= b && b <= 12) {
				ans = "YYMM";
			} else if (1 <= a && a <= 12 && 0 <= b && b <= 99) {
				ans = "MMYY";
			}
			out.println(ans);
		} String S = in.next(); S in.next() in.next in int a = Integer.parseInt(S.substring(0, 2)); a Integer.parseInt(S.substring(0, 2)) Integer.parseInt Integer S.substring(0, 2) S.substring S 0 2 int b = Integer.parseInt(S.substring(2, 4)); b Integer.parseInt(S.substring(2, 4)) Integer.parseInt Integer S.substring(2, 4) S.substring S 2 4 String ans = "NA"; ans "NA" if ((0 <= a && a <= 99 && 1 <= b && b <= 12) && (1 <= a && a <= 12 && 0 <= b && b <= 99)) {
				ans = "AMBIGUOUS";
			} else if (0 <= a && a <= 99 && 1 <= b && b <= 12) {
				ans = "YYMM";
			} else if (1 <= a && a <= 12 && 0 <= b && b <= 99) {
				ans = "MMYY";
			} (0 <= a && a <= 99 && 1 <= b && b <= 12) && (1 <= a && a <= 12 && 0 <= b && b <= 99) (0 <= a && a <= 99 && 1 <= b && b <= 12) 1 <= b 0 <= a && a <= 99 && 1 <= b && b <= 12 0 <= a 0 a a <= 99 a 99 1 <= b 1 b b <= 12 b 12 (1 <= a && a <= 12 && 0 <= b && b <= 99) 0 <= b 1 <= a && a <= 12 && 0 <= b && b <= 99 1 <= a 1 a a <= 12 a 12 0 <= b 0 b b <= 99 b 99 {
				ans = "AMBIGUOUS";
			} ans = "AMBIGUOUS" ans "AMBIGUOUS" if (0 <= a && a <= 99 && 1 <= b && b <= 12) {
				ans = "YYMM";
			} else if (1 <= a && a <= 12 && 0 <= b && b <= 99) {
				ans = "MMYY";
			} 0 <= a && a <= 99 && 1 <= b && b <= 12 1 <= b 0 <= a && a <= 99 && 1 <= b && b <= 12 0 <= a 0 a a <= 99 a 99 1 <= b 1 b b <= 12 b 12 {
				ans = "YYMM";
			} ans = "YYMM" ans "YYMM" if (1 <= a && a <= 12 && 0 <= b && b <= 99) {
				ans = "MMYY";
			} 1 <= a && a <= 12 && 0 <= b && b <= 99 0 <= b 1 <= a && a <= 12 && 0 <= b && b <= 99 1 <= a 1 a a <= 12 a 12 0 <= b 0 b b <= 99 b 99 {
				ans = "MMYY";
			} ans = "MMYY" ans "MMYY" out.println(ans) out.println out ans int testNumber testNumber InputReader in in PrintWriter out out static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public InputReader(InputStream stream) {
			reader = new BufferedReader(new InputStreamReader(stream), 32768);
			tokenizer = null;
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

		public char nextChar() {
			return next().charAt(0);
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}

		public double nextDouble() {
			return Double.parseDouble(next());
		}

		public long nextLong() {
			return Long.parseLong(next());
		}

	} InputReader public BufferedReader reader; reader public StringTokenizer tokenizer; tokenizer public InputReader(InputStream stream) {
			reader = new BufferedReader(new InputStreamReader(stream), 32768);
			tokenizer = null;
		} InputReader {
			reader = new BufferedReader(new InputStreamReader(stream), 32768);
			tokenizer = null;
		} reader = new BufferedReader(new InputStreamReader(stream), 32768) reader new BufferedReader(new InputStreamReader(stream), 32768) tokenizer = null tokenizer null InputStream stream stream public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		} next {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		} while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			} tokenizer == null || !tokenizer.hasMoreTokens() tokenizer == null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			} try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				} catch (IOException e) {
					throw new RuntimeException(e);
				} IOException e {
					throw new RuntimeException(e);
				} throw new RuntimeException(e); new RuntimeException(e) {
					tokenizer = new StringTokenizer(reader.readLine());
				} tokenizer = new StringTokenizer(reader.readLine()) tokenizer new StringTokenizer(reader.readLine()) return tokenizer.nextToken(); tokenizer.nextToken() tokenizer.nextToken tokenizer public char nextChar() {
			return next().charAt(0);
		} nextChar {
			return next().charAt(0);
		} return next().charAt(0); next().charAt(0) next().charAt next() next 0 public int nextInt() {
			return Integer.parseInt(next());
		} nextInt {
			return Integer.parseInt(next());
		} return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next public double nextDouble() {
			return Double.parseDouble(next());
		} nextDouble {
			return Double.parseDouble(next());
		} return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next public long nextLong() {
			return Long.parseLong(next());
		} nextLong {
			return Long.parseLong(next());
		} return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		Task solver = new Task();
		solver.solve(1, in, out);
		out.close();
	}

	static class Task {
		public void solve(int testNumber, InputReader in, PrintWriter out) {
			String S = in.next();
			int a = Integer.parseInt(S.substring(0, 2));
			int b = Integer.parseInt(S.substring(2, 4));
			String ans = "NA";
			if ((0 <= a && a <= 99 && 1 <= b && b <= 12) && (1 <= a && a <= 12 && 0 <= b && b <= 99)) {
				ans = "AMBIGUOUS";
			} else if (0 <= a && a <= 99 && 1 <= b && b <= 12) {
				ans = "YYMM";
			} else if (1 <= a && a <= 12 && 0 <= b && b <= 99) {
				ans = "MMYY";
			}
			out.println(ans);
		}
	}

	static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public InputReader(InputStream stream) {
			reader = new BufferedReader(new InputStreamReader(stream), 32768);
			tokenizer = null;
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

		public char nextChar() {
			return next().charAt(0);
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}

		public double nextDouble() {
			return Double.parseDouble(next());
		}

		public long nextLong() {
			return Long.parseLong(next());
		}

	}
} public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		Task solver = new Task();
		solver.solve(1, in, out);
		out.close();
	}

	static class Task {
		public void solve(int testNumber, InputReader in, PrintWriter out) {
			String S = in.next();
			int a = Integer.parseInt(S.substring(0, 2));
			int b = Integer.parseInt(S.substring(2, 4));
			String ans = "NA";
			if ((0 <= a && a <= 99 && 1 <= b && b <= 12) && (1 <= a && a <= 12 && 0 <= b && b <= 99)) {
				ans = "AMBIGUOUS";
			} else if (0 <= a && a <= 99 && 1 <= b && b <= 12) {
				ans = "YYMM";
			} else if (1 <= a && a <= 12 && 0 <= b && b <= 99) {
				ans = "MMYY";
			}
			out.println(ans);
		}
	}

	static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public InputReader(InputStream stream) {
			reader = new BufferedReader(new InputStreamReader(stream), 32768);
			tokenizer = null;
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

		public char nextChar() {
			return next().charAt(0);
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}

		public double nextDouble() {
			return Double.parseDouble(next());
		}

		public long nextLong() {
			return Long.parseLong(next());
		}

	}
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Deque;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.function.BiConsumer;

/**
 * Built using CHelper plug-in Actual solution is at the top
 */

public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		Task solver = new Task();
		solver.solve(1, in, out);
		out.close();
	}

	static class Task {
		public void solve(int testNumber, InputReader in, PrintWriter out) {
			String S = in.next();
			int a = Integer.parseInt(S.substring(0, 2));
			int b = Integer.parseInt(S.substring(2, 4));
			String ans = "NA";
			if ((0 <= a && a <= 99 && 1 <= b && b <= 12) && (1 <= a && a <= 12 && 0 <= b && b <= 99)) {
				ans = "AMBIGUOUS";
			} else if (0 <= a && a <= 99 && 1 <= b && b <= 12) {
				ans = "YYMM";
			} else if (1 <= a && a <= 12 && 0 <= b && b <= 99) {
				ans = "MMYY";
			}
			out.println(ans);
		}
	}

	static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public InputReader(InputStream stream) {
			reader = new BufferedReader(new InputStreamReader(stream), 32768);
			tokenizer = null;
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

		public char nextChar() {
			return next().charAt(0);
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}

		public double nextDouble() {
			return Double.parseDouble(next());
		}

		public long nextLong() {
			return Long.parseLong(next());
		}

	}
}
