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


public class UnionFind
{
    private int[] _par;
    private int[] _rank;

    public UnionFind(int size)
    {
        _par = new int[size + 1];
        _rank = new int[size + 1];
        for (int i = 0; i < _par.Length; i++)
        {
            _par[i] = i;
        }
    }

    public int Root(int x)
    {
        if (_par[x] == x)
            return x;
        else
        {
            _par[x] = Root(_par[x]);
            return _par[x];
        }
    }

    public bool IsSame(int x, int y)
    {
        return Root(x) == Root(y);
    }

    public void Unite(int x, int y)
    {
        x = Root(x);
        y = Root(y);
        if (x == y) return;

        if (_rank[x] < _rank[y])
        {
            _par[x] = y;
        }
        else
        {
            _par[y] = x;
            if (_rank[x] == _rank[y])
            {
                _rank[x]++;
            }
        }
    }
}
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++)
        {
            UnionFind union = new UnionFind(N);
            for (int j = 0; j < M; j++)
            {
                if(j == i)
                {
                    continue;
                }
                int a = input_route[j, 0];
                int b = input_route[j, 1];
                union.Unite(a, b);
            }
            HashSet<int> check = new HashSet<int>();
            for(int n = 0;n < N; n++)
            {
                check.Add(union.Root(n));
            }
            
            if (check.Count == 1)
            {
                ret++;
            }
        }
        
        Console.WriteLine(M-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: 13280