// ReSharper disable ArrangeTypeMemberModifiers
// ReSharper disable ConvertIfStatementToSwitchStatement
// ReSharper disable FunctionRecursiveOnAllPaths
// ReSharper disable InconsistentNaming
// ReSharper disable InlineOutVariableDeclaration
// ReSharper disable InvertIf
// ReSharper disable JoinDeclarationAndInitializer
// ReSharper disable MemberCanBeMadeStatic.Global
// ReSharper disable MemberCanBeMadeStatic.Local
// ReSharper disable NonReadonlyMemberInGetHashCode
// ReSharper disable PossibleNullReferenceException
// ReSharper disable RedundantUsingDirective
// ReSharper disable SuggestVarOrType_BuiltInTypes
// ReSharper disable SuggestVarOrType_Elsewhere
// ReSharper disable TailRecursiveCall
// ReSharper disable UnusedMember.Global
// ReSharper disable UnusedMember.Local
// ReSharper disable UseObjectOrCollectionInitializert

#if true && UTAKA_LOCAL

//#if false
#define UTAKA_DEBUG
#endif

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Numerics;
using System.Runtime.InteropServices;
using System.Security.Cryptography;

namespace UtakaApp
{
    public partial class Program
    {
        public const string SiteName    = "AtCoder";
        public const string ContestName = "agc026";
        public const string ProblemName = "C";

        public void Solve()
        {
            int    N = cin.ReadInt;
            string S = cin.Read;

            string s1 = S.Substring(0, N);
            string s2 = S.Substring(N, N);

            s2 = new string(s2.ToCharArray().Reverse().ToArray());

            List<char> c1r = new List<char>();
            List<char> c1b = new List<char>();

            List<char> c2r = new List<char>();
            List<char> c2b = new List<char>();

            Dictionary<Pair<string, string>, long> s1Dict = new Dictionary<Pair<string, string>, long>();
            Dictionary<Pair<string, string>, long> s2Dict = new Dictionary<Pair<string, string>, long>();

            for (int bit = 0; bit < (1 << N); bit++)
            {
                c1r.Clear();
                c1b.Clear();
                c2r.Clear();
                c2b.Clear();

                for (int i = 0; i < N; i++)
                {
                    if ((bit & (1 << i)) != 0)
                    {
                        c1r.Add(s1[i]);
                        c2r.Add(s2[i]);
                    }
                    else
                    {
                        c1b.Add(s1[i]);
                        c2b.Add(s2[i]);
                    }
                }

                string res1r = new string(c1r.ToArray());
                string res1b = new string(c1b.ToArray());
                string res2r = new string(c2r.ToArray());
                string res2b = new string(c2b.ToArray());

                Pair p1 = new Pair(res1r, res1b);
                Pair p2 = new Pair(res2r, res2b);

                if (!s1Dict.ContainsKey(p1))
                {
                    s1Dict.Add(p1, 0);
                }

                s1Dict[p1]++;

                if (!s2Dict.ContainsKey(p2))
                {
                    s2Dict.Add(p2, 0);
                }

                s2Dict[p2]++;
            }

            long ans = 0;

            foreach (Pair<string, string> pair in s1Dict.Keys)
            {
                if (!s2Dict.ContainsKey(pair))
                {
                    continue;
                }

                long count1 = s1Dict[pair];
                long count2 = s2Dict[pair];

                ans += count1 * count2;
            }

            cou.WriteLine(ans);
        }
    }

    public sealed class Pair : Pair<string, string>
    {
        public Pair(string first, string second) : base(first, second)
        {
        }
    }

    [DebuggerDisplay("({First}, {Second})")]
    public class Pair<T1, T2> : IComparable<Pair<T1, T2>>, IEquatable<Pair<T1, T2>>
        where T1 : IComparable<T1>
        where T2 : IComparable<T2>
    {
        public Pair(T1 first, T2 second)
        {
            First  = first;
            Second = second;
        }

        public T1 First;
        public T2 Second;

        public int CompareTo(Pair<T1, T2> other)
        {
            if (ReferenceEquals(this, other)) return 0;
            if (ReferenceEquals(null, other)) return 1;
            var firstComparison = First.CompareTo(other.First);
            return firstComparison != 0 ? firstComparison : Second.CompareTo(other.Second);
        }

        public override string ToString() => $"({First}, {Second})";

        public bool Equals(Pair<T1, T2> other)
        {
            if (ReferenceEquals(null, other)) return false;
            if (ReferenceEquals(this, other)) return true;
            return EqualityComparer<T1>.Default.Equals(First, other.First) &&
                   EqualityComparer<T2>.Default.Equals(Second, other.Second);
        }

        public override bool Equals(object obj)
        {
            if (ReferenceEquals(null, obj)) return false;
            if (ReferenceEquals(this, obj)) return true;
            return obj.GetType() == this.GetType() && Equals((Pair<T1, T2>)obj);
        }

        public override int GetHashCode()
        {
            unchecked
            {
                return (EqualityComparer<T1>.Default.GetHashCode(First) * 397) ^
                       EqualityComparer<T2>.Default.GetHashCode(Second);
            }
        }
    }


//=========================================================================================
// Debug IO
//=========================================================================================

    public partial class Program
    {
        //=========================================================================================
        // Main
        //=========================================================================================

        private readonly ConsoleInput cin;
        private readonly IConsole     cou;

        public Program(ConsoleInput cin, IConsole cou)
        {
            this.cin = cin;
            this.cou = cou;
        }

        public static void Main(string[] args)
        {
#if UTAKA_LOCAL
//#if false
            new TestCaseCheckerForAtCoder().TestProblems();
#else
            var cin = new ConsoleInput(System.Console.In);
            var console = new MyConsole();
            new Program(cin, console).Solve();
            console.Flush();
#endif
        }

        //=========================================================================================
        // Library
        //=========================================================================================

        public static T[] Array1D<T>(int a, T defaultValue)
            where T : struct
        {
            var ret = new T[a];
            for (int i = 0; i < a; i++)
            {
            }

            return ret;
        }

        public static T[] Array1D<T>(int a)
            where T : struct
        {
            var ret = new T[a];
            return ret;
        }

        /// <summary>
        /// 要素数 (a, b) の、defaultValue で満たされた配列を作成します。
        /// </summary>
        /// <typeparam name="T">配列の型</typeparam>
        /// <param name="a">1次元の要素数</param>
        /// <param name="b">2次元の要素数</param>
        /// <param name="defaultValue">デフォルト値</param>
        /// <returns>指定した条件で初期化された配列</returns>
        public static T[,] Array2D<T>(int a, int b, T defaultValue)
            where T : struct
        {
            var ret = new T[a, b];
            for (int i = 0; i < a; i++)
            {
                for (int j = 0; j < b; j++)
                {
                    ret[i, j] = defaultValue;
                }
            }

            return ret;
        }

        public static T[,,] Array3D<T>(int a, int b, int c, T defaultValue)
            where T : struct
        {
            T[,,] ret = new T[a, b, c];

            for (int i = 0; i < a; i++)
            {
                for (int j = 0; j < b; j++)
                {
                    for (int k = 0; k < c; k++)
                    {
                        ret[i, j, k] = defaultValue;
                    }
                }
            }

            return ret;
        }

        /// <summary>
        /// 要素数 (a, b) の、defaultValue で満たされたJag配列を作成します。
        /// </summary>
        /// <typeparam name="T">配列の型</typeparam>
        /// <param name="a">1次元の要素数</param>
        /// <param name="b">2次元の要素数</param>
        /// <param name="defaultValue">デフォルト値</param>
        /// <returns>指定した条件で初期化された配列</returns>
        public static T[][] JagArray2D<T>(int a, int b, T defaultValue)
            where T : struct
        {
            var ret = new T[a][];
            for (int i = 0; i < a; i++)
            {
                var row = new T[b];
                ret[i] = row;

                for (int j = 0; j < b; j++)
                {
                    row[j] = defaultValue;
                }
            }

            return ret;
        }

        /// <summary>
        /// 要素数 (a, b) のdefault値で満たされたJag配列を作成します。
        /// </summary>
        /// <typeparam name="T">配列の型</typeparam>
        /// <param name="a">1次元の要素数</param>
        /// <param name="b">2次元の要素数</param>
        /// <returns>初期化された配列</returns>
        public static T[][] JagArray2D<T>(int a, int b)
            where T : struct
        {
            var ret = new T[a][];
            for (int i = 0; i < a; i++)
            {
                ret[i] = new T[b];
            }

            return ret;
        }

        public static T[][][] JagArray3D<T>(int a, int b, int c, T defaultValue)
            where T : struct
        {
            var ret = new T[a][][];
            for (int i = 0; i < a; i++)
            {
                T[][] aRow = new T[b][];
                ret[i] = aRow;

                for (int j = 0; j < b; j++)
                {
                    T[] bRow = new T[c];
                    aRow[j] = bRow;

                    for (int k = 0; k < c; k++)
                    {
                        bRow[k] = defaultValue;
                    }
                }
            }

            return ret;
        }

        public static T[][][] JagArray3D<T>(int a, int b, int c)
            where T : struct
        {
            var ret = new T[a][][];
            for (int i = 0; i < a; i++)
            {
                T[][] aRow = new T[b][];
                ret[i] = aRow;

                for (int j = 0; j < b; j++)
                {
                    T[] bRow = new T[c];
                    aRow[j] = bRow;
                }
            }

            return ret;
        }

        public static T[][][][] JagArray4D<T>(int a, int b, int c, int d, T defaultValue)
            where T : struct
        {
            var ret = new T[a][][][];
            for (int i = 0; i < a; i++)
            {
                T[][][] aRow = new T[b][][];
                ret[i] = aRow;

                for (int j = 0; j < b; j++)
                {
                    T[][] bRow = new T[c][];
                    aRow[j] = bRow;

                    for (int k = 0; k < c; k++)
                    {
                        T[] cRow = new T[d];
                        bRow[k] = cRow;

                        for (int l = 0; l < d; l++)
                        {
                            cRow[l] = defaultValue;
                        }
                    }
                }
            }

            return ret;
        }

        public static T[][][][] JagArray4D<T>(int a, int b, int c, int d)
            where T : struct
        {
            var ret = new T[a][][][];
            for (int i = 0; i < a; i++)
            {
                T[][][] aRow = new T[b][][];
                ret[i] = aRow;

                for (int j = 0; j < b; j++)
                {
                    T[][] bRow = new T[c][];
                    aRow[j] = bRow;

                    for (int k = 0; k < c; k++)
                    {
                        T[] cRow = new T[d];
                        bRow[k] = cRow;
                    }
                }
            }

            return ret;
        }

        public static T[][][][][] JagArray5D<T>(int a, int b, int c, int d, int e, T defaultValue)
            where T : struct
        {
            var ret = new T[a][][][][];
            for (int i = 0; i < a; i++)
            {
                T[][][][] aRow = new T[b][][][];
                ret[i] = aRow;

                for (int j = 0; j < b; j++)
                {
                    T[][][] bRow = new T[c][][];
                    aRow[j] = bRow;

                    for (int k = 0; k < c; k++)
                    {
                        T[][] cRow = new T[d][];
                        bRow[k] = cRow;

                        for (int l = 0; l < d; l++)
                        {
                            T[] dRow = new T[e];
                            cRow[l] = dRow;

                            for (int m = 0; m < e; m++)
                            {
                                dRow[m] = defaultValue;
                            }
                        }
                    }
                }
            }

            return ret;
        }

        public static T[][][][][] JagArray5D<T>(int a, int b, int c, int d, int e)
            where T : struct
        {
            var ret = new T[a][][][][];
            for (int i = 0; i < a; i++)
            {
                T[][][][] aRow = new T[b][][][];
                ret[i] = aRow;

                for (int j = 0; j < b; j++)
                {
                    T[][][] bRow = new T[c][][];
                    aRow[j] = bRow;

                    for (int k = 0; k < c; k++)
                    {
                        T[][] cRow = new T[d][];
                        bRow[k] = cRow;

                        for (int l = 0; l < d; l++)
                        {
                            T[] dRow = new T[e];
                            cRow[l] = dRow;
                        }
                    }
                }
            }

            return ret;
        }

        /// <summary>
        /// ジャグ配列をコピーして返す。
        /// </summary>
        public static T[][] CopyJagArray2D<T>(T[][] source)
            where T : struct
        {
            int   len  = source.Length;
            T[][] dest = new T[len][];

            for (int i = 0; i < len; i++)
            {
                T[] inner       = source[i];
                int innerLength = inner.Length;
                T[] newer       = new T[innerLength];
                Array.Copy(inner, newer, innerLength);
                dest[i] = newer;
            }

            return dest;
        }
    }

    public class IntLargeComparer : IComparer<int>
    {
        public static IntLargeComparer Instance = new IntLargeComparer();

        public int Compare(int x, int y)
        {
            return y - x;
        }
    }

    public class LongLargeComparer : IComparer<long>
    {
        public static LongLargeComparer Instance = new LongLargeComparer();

        public int Compare(long x, long y)
        {
            if (x > y) return -1;
            if (x < y) return 1;
            return 0;
        }
    }

    public static class UtakaExtentions
    {
        /// <summary>
        /// 配列をコピーします
        /// </summary>
        public static T[] Copy<T>(this IList<T> a)
        {
            T[] ret = new T[a.Count];

            for (int i = 0; i < a.Count; i++) ret[i] = a[i];

            return ret;
        }
    }

    public class ConsoleInput
    {
        private readonly char          _separator = ' ';
        private readonly TextReader    _stream;
        private readonly Queue<string> inputStream;

        public ConsoleInput(TextReader stream, char separator = ' ')
        {
            _separator  = separator;
            _stream     = stream;
            inputStream = new Queue<string>();
        }

        public string Read
        {
            get
            {
                if (inputStream.Count != 0)
                {
                    return inputStream.Dequeue();
                }

                var tmp = _stream.ReadLine().Split(_separator);
                for (var i = 0; i < tmp.Length; ++i)
                {
                    inputStream.Enqueue(tmp[i]);
                }

                return inputStream.Dequeue();
            }
        }

        public string ReadLine   => _stream.ReadLine();
        public int    ReadInt    => int.Parse(Read);
        public long   ReadLong   => long.Parse(Read);
        public double ReadDouble => double.Parse(Read);

        public string[] ReadStrArray(long N)
        {
            var ret = new string[N];
            for (long i = 0; i < N; ++i)
            {
                ret[i] = Read;
            }

            return ret;
        }

        public int[] ReadIntArray(long N)
        {
            var ret = new int[N];
            for (long i = 0; i < N; ++i)
            {
                ret[i] = ReadInt;
            }

            return ret;
        }

        public long[] ReadLongArray(long N)
        {
            var ret = new long[N];
            for (long i = 0; i < N; ++i)
            {
                ret[i] = ReadLong;
            }

            return ret;
        }
    }

    public interface IConsole
    {
        void Flush();
        void Write(object obj);
        void Write(string str);
        void WriteLine(object obj);
        void WriteLine(string str);
        void WriteLine();
    }

    public class MyConsole : IConsole
    {
        public MyConsole()
        {
            var sw = new StreamWriter(Console.OpenStandardOutput()) {AutoFlush = false};
            Console.SetOut(sw);
        }

        public void Flush()
        {
            Console.Out.Flush();
        }

        public void Write(object obj)
        {
            Write(obj.ToString());
        }

        public void Write(string str)
        {
            Console.Write(str);
        }

        public void WriteLine(object obj)
        {
            WriteLine(obj.ToString());
        }

        public void WriteLine(string str)
        {
            Console.WriteLine(str);
        }

        public void WriteLine()
        {
            Console.WriteLine();
        }
    }

#if UTAKA_LOCAL

    public class DebugConsole : IConsole
    {
        private readonly StringBuilder mSb;

        public DebugConsole()
        {
            mSb = new StringBuilder();
        }

        public void Flush()
        {
            // 何もしない
        }

        public void Write(object obj)
        {
            Write(obj.ToString());
        }

        public void Write(string str)
        {
            mSb.Append(str);
        }

        public void WriteLine(object obj)
        {
            WriteLine(obj.ToString());
        }

        public void WriteLine(string str)
        {
            mSb.AppendLine(str);
        }

        public void WriteLine()
        {
            mSb.AppendLine();
        }

        public string GetAllOutput()
        {
            return mSb.ToString();
        }
    }

#endif

#if UTAKA_LOCAL

    public class TestCaseCheckerForAtCoder
    {
        private string GetDirectoryPath()
        {
            var problemPart = string.IsNullOrEmpty(Program.ProblemName)
                ? ""
                : $"/{Program.ProblemName}";

            return
                $"{Environment.GetFolderPath(Environment.SpecialFolder.UserProfile)}/AlgorithmPrac/{Program.SiteName}/{Program.ContestName}{problemPart}";
        }

        private string GetInputFilePath(int testCaseNumber)
        {
            return $"{GetDirectoryPath()}/sample-{testCaseNumber}.in";
        }

        private string GetOutputFilePath(int testCaseNumber)
        {
            return $"{GetDirectoryPath()}/sample-{testCaseNumber}.out";
        }

        public bool TestProblem(int testCaseNumber)
        {
            var inputFilePath  = GetInputFilePath(testCaseNumber);
            var outputFilePath = GetOutputFilePath(testCaseNumber);

            TextReader inputStream = new StreamReader(inputFilePath);
            var        cin         = new ConsoleInput(inputStream);

            var debugConsoleWriter = new DebugConsole();

            new Program(cin, debugConsoleWriter).Solve();

            var output = debugConsoleWriter.GetAllOutput();

            TextReader outputStream = new StreamReader(outputFilePath);
            var        outputAnswer = outputStream.ReadToEnd();

            Dbg.WriteLine(output);
            Dbg.WriteLine(outputAnswer);

            var isCorrect = output == outputAnswer;

            return isCorrect;
        }

        public void TestProblems(int targetTestCaseNumber = -1)
        {
            if (targetTestCaseNumber >= 0)
            {
                Console.WriteLine($"!!!!!!!!!!!! Check TestCase {targetTestCaseNumber} !!!!!!!!!!");
            }

            bool isSuccessAll = true;

            int testCaseNumber = 0;
            while (true)
            {
                testCaseNumber++;

                bool foundTargetTest = targetTestCaseNumber == testCaseNumber;

                if (targetTestCaseNumber >= 0 && !foundTargetTest)
                {
                    continue;
                }

                var inputFileName = GetInputFilePath(testCaseNumber);
                if (!File.Exists(inputFileName))
                {
                    break;
                }

                Console.WriteLine($"TestCase {testCaseNumber} =====================================================");

                var result = TestProblem(testCaseNumber);

                if (result)
                {
                    Console.WriteLine("Success");
                }
                else
                {
                    isSuccessAll = false;
                    Console.WriteLine("Failure *****");
                }

                if (foundTargetTest)
                {
                    break;
                }
            }

            if (isSuccessAll)
            {
                Console.WriteLine("!!!!!!!!! All Success !!!!!!!!!");
            }
        }
    }

#endif

    public static class Dbg
    {
        [Conditional("UTAKA_DEBUG")]
        public static void WriteLine(string str)
        {
            Console.WriteLine(str);
        }

        [Conditional("UTAKA_DEBUG")]
        public static void WriteLine()
        {
            Console.WriteLine();
        }

        [Conditional("UTAKA_DEBUG")]
        public static void Write(string str)
        {
            Console.Write(str);
        }
    }
}


Measured memory_bytes: 96012