import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Sparsh Sanchorawala
 */
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);
        BYYMMOrMMYY solver = new BYYMMOrMMYY();
        solver.solve(1, in, out);
        out.close();
    }

    static class BYYMMOrMMYY {
        public void solve(int testNumber, InputReader s, PrintWriter w) {
            String a = s.next();
            boolean f1 = false, f2 = false;
            int a1 = Integer.parseInt(a.substring(0, 2));
            int a2 = Integer.parseInt(a.substring(2, 4));
            if (a1 <= 12 && a1 >= 1)
                f1 = true;
            if (a2 <= 12 && a2 >= 1)
                f2 = true;
            if (f1) {
                if (f2) {
                    w.println("AMBIGUOUS");
                } else
                    w.println("MMYY");
            } else {
                if (f2)
                    w.println("YYMM");
                else
                    w.println("NA");
            }

        }

    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private InputReader.SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public String nextString() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                }
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public String next() {
            return nextString();
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.InputMismatchException; InputMismatchException java.util import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io 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);
        BYYMMOrMMYY solver = new BYYMMOrMMYY();
        solver.solve(1, in, out);
        out.close();
    }

    static class BYYMMOrMMYY {
        public void solve(int testNumber, InputReader s, PrintWriter w) {
            String a = s.next();
            boolean f1 = false, f2 = false;
            int a1 = Integer.parseInt(a.substring(0, 2));
            int a2 = Integer.parseInt(a.substring(2, 4));
            if (a1 <= 12 && a1 >= 1)
                f1 = true;
            if (a2 <= 12 && a2 >= 1)
                f2 = true;
            if (f1) {
                if (f2) {
                    w.println("AMBIGUOUS");
                } else
                    w.println("MMYY");
            } else {
                if (f2)
                    w.println("YYMM");
                else
                    w.println("NA");
            }

        }

    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private InputReader.SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public String nextString() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                }
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public String next() {
            return nextString();
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }
} 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);
        BYYMMOrMMYY solver = new BYYMMOrMMYY();
        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);
        BYYMMOrMMYY solver = new BYYMMOrMMYY();
        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) BYYMMOrMMYY solver = new BYYMMOrMMYY(); solver new BYYMMOrMMYY() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class BYYMMOrMMYY {
        public void solve(int testNumber, InputReader s, PrintWriter w) {
            String a = s.next();
            boolean f1 = false, f2 = false;
            int a1 = Integer.parseInt(a.substring(0, 2));
            int a2 = Integer.parseInt(a.substring(2, 4));
            if (a1 <= 12 && a1 >= 1)
                f1 = true;
            if (a2 <= 12 && a2 >= 1)
                f2 = true;
            if (f1) {
                if (f2) {
                    w.println("AMBIGUOUS");
                } else
                    w.println("MMYY");
            } else {
                if (f2)
                    w.println("YYMM");
                else
                    w.println("NA");
            }

        }

    } BYYMMOrMMYY public void solve(int testNumber, InputReader s, PrintWriter w) {
            String a = s.next();
            boolean f1 = false, f2 = false;
            int a1 = Integer.parseInt(a.substring(0, 2));
            int a2 = Integer.parseInt(a.substring(2, 4));
            if (a1 <= 12 && a1 >= 1)
                f1 = true;
            if (a2 <= 12 && a2 >= 1)
                f2 = true;
            if (f1) {
                if (f2) {
                    w.println("AMBIGUOUS");
                } else
                    w.println("MMYY");
            } else {
                if (f2)
                    w.println("YYMM");
                else
                    w.println("NA");
            }

        } solve {
            String a = s.next();
            boolean f1 = false, f2 = false;
            int a1 = Integer.parseInt(a.substring(0, 2));
            int a2 = Integer.parseInt(a.substring(2, 4));
            if (a1 <= 12 && a1 >= 1)
                f1 = true;
            if (a2 <= 12 && a2 >= 1)
                f2 = true;
            if (f1) {
                if (f2) {
                    w.println("AMBIGUOUS");
                } else
                    w.println("MMYY");
            } else {
                if (f2)
                    w.println("YYMM");
                else
                    w.println("NA");
            }

        } String a = s.next(); a s.next() s.next s boolean f1 = false f1 false f2 = false; f2 false int a1 = Integer.parseInt(a.substring(0, 2)); a1 Integer.parseInt(a.substring(0, 2)) Integer.parseInt Integer a.substring(0, 2) a.substring a 0 2 int a2 = Integer.parseInt(a.substring(2, 4)); a2 Integer.parseInt(a.substring(2, 4)) Integer.parseInt Integer a.substring(2, 4) a.substring a 2 4 if (a1 <= 12 && a1 >= 1)
                f1 = true; a1 <= 12 && a1 >= 1 a1 <= 12 a1 12 a1 >= 1 a1 1 f1 = true f1 true if (a2 <= 12 && a2 >= 1)
                f2 = true; a2 <= 12 && a2 >= 1 a2 <= 12 a2 12 a2 >= 1 a2 1 f2 = true f2 true if (f1) {
                if (f2) {
                    w.println("AMBIGUOUS");
                } else
                    w.println("MMYY");
            } else {
                if (f2)
                    w.println("YYMM");
                else
                    w.println("NA");
            } f1 {
                if (f2) {
                    w.println("AMBIGUOUS");
                } else
                    w.println("MMYY");
            } if (f2) {
                    w.println("AMBIGUOUS");
                } else
                    w.println("MMYY"); f2 {
                    w.println("AMBIGUOUS");
                } w.println("AMBIGUOUS") w.println w "AMBIGUOUS" w.println("MMYY") w.println w "MMYY" {
                if (f2)
                    w.println("YYMM");
                else
                    w.println("NA");
            } if (f2)
                    w.println("YYMM");
                else
                    w.println("NA"); f2 w.println("YYMM") w.println w "YYMM" w.println("NA") w.println w "NA" int testNumber testNumber InputReader s s PrintWriter w w static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private InputReader.SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public String nextString() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                }
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public String next() {
            return nextString();
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    } InputReader private InputStream stream; stream private byte[] buf = new byte[1024]; buf new byte[1024] 1024 private int curChar; curChar private int numChars; numChars private InputReader.SpaceCharFilter filter; filter public InputReader(InputStream stream) {
            this.stream = stream;
        } InputReader {
            this.stream = stream;
        } this.stream = stream this.stream this this.stream stream InputStream stream stream public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        } read {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        } if (numChars == -1) {
                throw new InputMismatchException();
            } numChars == -1 numChars -1 1 {
                throw new InputMismatchException();
            } throw new InputMismatchException(); new InputMismatchException() if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            } curChar >= numChars curChar numChars {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            } curChar = 0 curChar 0 try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                } catch (IOException e) {
                    throw new InputMismatchException();
                } IOException e {
                    throw new InputMismatchException();
                } throw new InputMismatchException(); new InputMismatchException() {
                    numChars = stream.read(buf);
                } numChars = stream.read(buf) numChars stream.read(buf) stream.read stream buf if (numChars <= 0) {
                    return -1;
                } numChars <= 0 numChars 0 {
                    return -1;
                } return -1; -1 1 return buf[curChar++]; buf[curChar++] buf curChar++ curChar public String nextString() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                }
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        } nextString {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                }
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        } int c = read(); c read() read while (isSpaceChar(c)) {
                c = read();
            } isSpaceChar(c) isSpaceChar c {
                c = read();
            } c = read() c read() read StringBuilder res = new StringBuilder(); res new StringBuilder() do {
                if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                }
                c = read();
            } while (!isSpaceChar(c)); !isSpaceChar(c) isSpaceChar(c) isSpaceChar c {
                if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                }
                c = read();
            } if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                } Character.isValidCodePoint(c) Character.isValidCodePoint Character c {
                    res.appendCodePoint(c);
                } res.appendCodePoint(c) res.appendCodePoint res c c = read() c read() read return res.toString(); res.toString() res.toString res public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        } isSpaceChar {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        } if (filter != null) {
                return filter.isSpaceChar(c);
            } filter != null filter null {
                return filter.isSpaceChar(c);
            } return filter.isSpaceChar(c); filter.isSpaceChar(c) filter.isSpaceChar filter c return isWhitespace(c); isWhitespace(c) isWhitespace c int c c public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        } isWhitespace {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        } return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1; c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1 c == '\t' c == '\r' c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1 c == ' ' c ' ' c == '\n' c '\n' c == '\r' c '\r' c == '\t' c '\t' c == -1 c -1 1 int c c public String next() {
            return nextString();
        } next {
            return nextString();
        } return nextString(); nextString() nextString public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        } SpaceCharFilter public boolean isSpaceChar(int ch); isSpaceChar int ch ch 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);
        BYYMMOrMMYY solver = new BYYMMOrMMYY();
        solver.solve(1, in, out);
        out.close();
    }

    static class BYYMMOrMMYY {
        public void solve(int testNumber, InputReader s, PrintWriter w) {
            String a = s.next();
            boolean f1 = false, f2 = false;
            int a1 = Integer.parseInt(a.substring(0, 2));
            int a2 = Integer.parseInt(a.substring(2, 4));
            if (a1 <= 12 && a1 >= 1)
                f1 = true;
            if (a2 <= 12 && a2 >= 1)
                f2 = true;
            if (f1) {
                if (f2) {
                    w.println("AMBIGUOUS");
                } else
                    w.println("MMYY");
            } else {
                if (f2)
                    w.println("YYMM");
                else
                    w.println("NA");
            }

        }

    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private InputReader.SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public String nextString() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                }
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public String next() {
            return nextString();
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }
} 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);
        BYYMMOrMMYY solver = new BYYMMOrMMYY();
        solver.solve(1, in, out);
        out.close();
    }

    static class BYYMMOrMMYY {
        public void solve(int testNumber, InputReader s, PrintWriter w) {
            String a = s.next();
            boolean f1 = false, f2 = false;
            int a1 = Integer.parseInt(a.substring(0, 2));
            int a2 = Integer.parseInt(a.substring(2, 4));
            if (a1 <= 12 && a1 >= 1)
                f1 = true;
            if (a2 <= 12 && a2 >= 1)
                f2 = true;
            if (f1) {
                if (f2) {
                    w.println("AMBIGUOUS");
                } else
                    w.println("MMYY");
            } else {
                if (f2)
                    w.println("YYMM");
                else
                    w.println("NA");
            }

        }

    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private InputReader.SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public String nextString() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                }
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public String next() {
            return nextString();
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Sparsh Sanchorawala
 */
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);
        BYYMMOrMMYY solver = new BYYMMOrMMYY();
        solver.solve(1, in, out);
        out.close();
    }

    static class BYYMMOrMMYY {
        public void solve(int testNumber, InputReader s, PrintWriter w) {
            String a = s.next();
            boolean f1 = false, f2 = false;
            int a1 = Integer.parseInt(a.substring(0, 2));
            int a2 = Integer.parseInt(a.substring(2, 4));
            if (a1 <= 12 && a1 >= 1)
                f1 = true;
            if (a2 <= 12 && a2 >= 1)
                f2 = true;
            if (f1) {
                if (f2) {
                    w.println("AMBIGUOUS");
                } else
                    w.println("MMYY");
            } else {
                if (f2)
                    w.println("YYMM");
                else
                    w.println("NA");
            }

        }

    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private InputReader.SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public String nextString() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                }
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public String next() {
            return nextString();
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }
}

