using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.ExceptionServices;

namespace Contest
{
    class Program
    {
        private Scanner sc;
        private int N, M;
        private List<int>[] edge;
        private int loop;
        public void Solve()
        {
            sc = new Scanner();
            N = sc.NextInt();
            M = sc.NextInt();
            edge = new List<int>[N];
            for (int i = 0; i < N; i++)
            {
                edge[i] = new List<int>();
            }
            for (int i = 0; i < M; i++)
            {
                int a = sc.NextInt() - 1;
                int b = sc.NextInt() - 1;
                edge[a].Add(b);
                edge[b].Add(a);
            }

            loop = 1 << N;
            Console.WriteLine(Cnt(0, 1));
        }

        int Cnt(int pos, int l)
        {
            if (l == loop-1) return 1;
            int ans = 0;
            foreach (var i in edge[pos])
            {
                int bit = 1 << i;
                if ((l & bit) > 0) continue;
                ans += Cnt(i, l + bit);
            }

            return ans;
        }

        static void Main() => new Program().Solve();
    }
}

class Scanner
{
    public Scanner()
    {
        _stream = new StreamReader(Console.OpenStandardInput());
        _pos = 0;
        _line = new string[0];
        _separator = ' ';
    }
    private readonly char _separator;
    private readonly StreamReader _stream;
    private int _pos;
    private string[] _line;
    #region get a element
    public string Next()
    {
        if (_pos >= _line.Length)
        {
            _line = _stream.ReadLine().Split(_separator);
            _pos = 0;
        }
        return _line[_pos++];
    }
    public int NextInt()
    {
        return int.Parse(Next());
    }
    public long NextLong()
    {
        return long.Parse(Next());
    }
    public double NextDouble()
    {
        return double.Parse(Next());
    }
    #endregion
    #region convert array
    private int[] ToIntArray(string[] array)
    {
        var result = new int[array.Length];
        for (int i = 0; i < array.Length; i++)
        {
            result[i] = int.Parse(array[i]);
        }

        return result;
    }
    private long[] ToLongArray(string[] array)
    {
        var result = new long[array.Length];
        for (int i = 0; i < array.Length; i++)
        {
            result[i] = long.Parse(array[i]);
        }

        return result;
    }
    private double[] ToDoubleArray(string[] array)
    {
        var result = new double[array.Length];
        for (int i = 0; i < array.Length; i++)
        {
            result[i] = double.Parse(array[i]);
        }

        return result;
    }
    #endregion
    #region get array
    public string[] Array()
    {
        if (_pos >= _line.Length)
            _line = _stream.ReadLine().Split(_separator);
        _pos = _line.Length;
        return _line;
    }
    public int[] IntArray()
    {
        return ToIntArray(Array());
    }
    public long[] LongArray()
    {
        return ToLongArray(Array());
    }
    public double[] DoubleArray()
    {
        return ToDoubleArray(Array());
    }
    #endregion
}

Measured memory_bytes: 13268