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



class Myon
{
    public Myon() { }
    public static int Main()
    {
        cin = new Scanner();
        new Myon().calc();
        return 0;
    }

    static Scanner cin;

    // メンバ変数---
    int N;
    int M;
    int[,] input_route;
    int[] visited;
    // -------------

    void calc()
    {
        N = cin.nextInt();
        M = cin.nextInt();
        input_route = new int[M, 2];
        int ret = 0;
        for (int i = 0;i < M; i++)
        {
            input_route[i, 0] = cin.nextInt()-1;
            input_route[i, 1] = cin.nextInt()-1;
        }

        
        for (int i = 0; i < M; i++)
        {
            HashSet<int>[] route = new HashSet<int>[N];
            for (int j = 0; j < N; j++)
            {
                route[j] = new HashSet<int>();
            }
            for (int j = 0; j < M; j++)
            {
                if(j == i)
                {
                    continue;
                }
                int a = input_route[j, 0];
                int b = input_route[j, 1];
                route[a].Add(b);
                route[b].Add(a);
            }
            int[] visited = new int[N];
            visited[0] = 1;
            bool judge = dfs(0,ref visited, false, route);
            if (judge)
            {
                ret++;
            }
        }
        
        Console.WriteLine(M-ret);


    }

    bool dfs(int v, ref int[] visited, bool ret, HashSet<int>[] route)
    {
        if (visited.Sum() == visited.Length)
        {
            return true;
        }
        HashSet<int> to = route[v];
        foreach(int t in to)
        {
            if(visited[t] == 0)
            {
                visited[t] = 1;
                ret = dfs(t,ref visited, ret, route);
                if (ret)
                {
                    return ret;
                }
            }
        }
        return ret;
    }


    class Scanner
    {
        string[] s;
        int i;

        char[] cs = new char[] { ' ' };

        public Scanner()
        {
            s = new string[0];
            i = 0;
        }

        public string next()
        {
            if (i < s.Length) return s[i++];
            string st = Console.ReadLine();
            while (st == "") st = Console.ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            if (s.Length == 0) return next();
            i = 0;
            return s[i++];
        }

        public int nextInt()
        {
            return int.Parse(next());
        }
        public int[] ArrayInt(int N, int add = 0)
        {
            int[] Array = new int[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextInt() + add;
            }
            return Array;
        }

        public long nextLong()
        {
            return long.Parse(next());
        }

        public long[] ArrayLong(int N, long add = 0)
        {
            long[] Array = new long[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextLong() + add;
            }
            return Array;
        }

        public double nextDouble()
        {
            return double.Parse(next());
        }


        public double[] ArrayDouble(int N, double add = 0)
        {
            double[] Array = new double[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextDouble() + add;
            }
            return Array;
        }
    }
}

Measured memory_bytes: 13524