Problem:
Score: 100 points

Problem Statement

E869120's and square1001's 16-th birthday is coming soon.

Takahashi from AtCoder Kingdom gave them a round cake cut into 16 equal fan-shaped pieces.

E869120 and square1001 were just about to eat A and B of those pieces, respectively,

when they found a note attached to the cake saying that "the same person should not take two adjacent pieces of cake".

Can both of them obey the instruction in the note and take desired numbers of pieces of cake?

Constraints

A and B are integers between 1 and 16 (inclusive).

A+B is at most 16.

Input

Input is given from Standard Input in the following format:

A B

Output

If both E869120 and square1001 can obey the instruction in the note and take desired numbers of pieces of cake, print Yay!; otherwise, print :(.

Sample Input 1

5 4

Sample Output 1

Yay!

Both of them can take desired number of pieces as follows:

Sample Input 2

8 8

Sample Output 2

Yay!

Both of them can take desired number of pieces as follows:

Sample Input 3

11 4

Sample Output 3

:(

In this case, there is no way for them to take desired number of pieces, unfortunately.

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ProgrammingContest
{
    class Writer : IDisposable
    {
        private readonly System.IO.TextWriter writer;
        private StringBuilder sb;
        private readonly bool isReactive;
        public Writer(string path)
            : this(new System.IO.StreamWriter(path))
        {
        }
        public Writer(bool isReactive)
            : this(null, isReactive)
        {
        }
        public Writer(System.IO.TextWriter writer = null,
                        bool isReactive = false)
        {
            this.writer = (writer ?? Console.Out);
            this.isReactive = isReactive;
            if (!this.isReactive)
            {
                this.sb = new StringBuilder();
            }
        }
        public void Dispose()
        {
            if (!this.isReactive)
            {
                this.writer.Write(sb.ToString());
            }
            if (!this.writer.Equals(Console.Out))
            {
                this.writer.Dispose();
            }
        }
        public void Write(object val)
        {
            if (this.isReactive)
            {
                this.writer.Write(val.ToString());
                this.writer.Flush();
            }
            else
            {
                this.sb.Append(val.ToString());
            }
        }
        public void Write(string format, params object[] vals)
        {
            if (this.isReactive)
            {
                this.writer.Write(format, vals);
                this.writer.Flush();
            }
            else
            {
                this.sb.AppendFormat(format, vals);
            }
        }
        public void WriteLine(object val = null)
        {
            this.Write((val ?? string.Empty).ToString() + System.Environment.NewLine);
        }
        public void WriteLine(int val)
        {
            this.WriteLine(val.ToString());
        }
        public void WriteLine(long val)
        {
            this.WriteLine(val.ToString());
        }
        public void WriteLine(string val)
        {
            this.WriteLine((object)val);
        }
        public void WriteLine(string format, params object[] vals)
        {
            this.Write(format + System.Environment.NewLine, vals);
        }
    }

    class Scanner : IDisposable
    {
        private readonly Queue<string> buffer;
        private readonly char[] sep;
        private readonly System.IO.TextReader reader;
        public Scanner(string path, char[] sep = null)
            : this(new System.IO.StreamReader(path), sep)
        {
        }
        public Scanner(System.IO.TextReader reader = null,
                        char[] sep = null)
        {
            this.buffer = new Queue<string>();
            this.sep = (sep ?? new char[] { ' ' });
            this.reader = (reader ?? Console.In);
        }
        private void CheckBuffer()
        {
            if (this.buffer.Count == 0 && this.reader.Peek() != -1)
            {
                string str = string.Empty;
                for (; string.IsNullOrEmpty(str);
                    str = this.reader.ReadLine()) ;

                str.Split(this.sep).ToList()
                   .ForEach(el => this.buffer.Enqueue(el));
            }
        }

        public void Dispose()
        {
            if (!this.reader.Equals(Console.In))
            {
                this.reader.Dispose();
            }
        }

        public string Next
        {
            get
            {
                this.CheckBuffer();
                return this.buffer.Dequeue();
            }
        }
        public string[] GetStringArray(int N)
        {
            return Enumerable.Range(0, N)
                             .Select(e => this.Next)
                             .ToArray();
        }

        public int NextInt
        {
            get
            {
                return int.Parse(this.Next);
            }
        }
        public int[] GetIntArray(int N)
        {
            return Enumerable.Range(0, N)
                             .Select(e => this.NextInt)
                             .ToArray();
        }

        public double NextDouble
        {
            get
            {
                return double.Parse(this.Next);
            }
        }
        public double[] GetdoubleArray(int N)
        {
            return Enumerable.Range(0, N)
                             .Select(e => this.NextDouble)
                             .ToArray();
        }

        public long NextLong
        {
            get
            {
                return long.Parse(this.Next);
            }
        }
        public long[] GetLongArray(int N)
        {
            return Enumerable.Range(0, N)
                             .Select(e => this.NextLong)
                             .ToArray();
        }

        public bool IsEnd
        {
            get
            {
                this.CheckBuffer();
                return this.buffer.Count == 0;
            }
        }
    }

    class MainClass : IDisposable
    {
        Scanner sc;
        Writer wr;
        const string backPath = "..";
        private readonly char dirSep = System.IO.Path.DirectorySeparatorChar;
        private readonly string inFilePath = string.Empty;
        private readonly string outFilePath = string.Empty;
        public MainClass()
        {
            this.inFilePath = MainClass.backPath
                            + this.dirSep
                            + MainClass.backPath
                            + this.dirSep
                            + "in.txt";
            this.outFilePath = MainClass.backPath
                             + this.dirSep
                             + MainClass.backPath
                             + this.dirSep
                             + "out.txt";

            this.wr = new Writer(this.IsReactive);
            //this.wr = new Writer(this.outFilePath);
#if DEBUG
            if (!this.IsReactive)
            {
                this.sc = new Scanner(this.inFilePath);
            }
            else
            {
                this.sc = new Scanner();
            }
#else
            this.sc = new Scanner();
#endif
        }
        static void Main(string[] args)
        {
            using (var mainClass = new MainClass())
            {
                mainClass.Solve();
            }
        }

        public void Dispose()
        {
            if (this.sc != null)
            {
                this.sc.Dispose();
                this.sc = null;
            }
            if (this.wr != null)
            {
                this.wr.Dispose();
                this.wr = null;
            }
#if DEBUG
            Console.WriteLine("続行するには何かキーを押してください...");
            Console.ReadKey();
#endif
        }

        void MakeTestCase()
        {
            var rand = new Random();
            if (this.wr != null)
            {
                this.wr.Dispose();
            }
            this.wr = new Writer(inFilePath);
        }

        void Solve()
        {
            int a = sc.NextInt;
            int b = sc.NextInt;
            wr.WriteLine(a > 8 || b > 8 ? ":(" : "Yay!");
        }
        private bool IsReactive { get; } = false; // TODO: reactive check !!
    }
}