import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.StringTokenizer;
import java.util.HashMap;
import java.io.IOException;
import java.util.InputMismatchException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();

            int[] from = new int[m];
            int[] to = new int[m];
            for (int i = 0; i < m; i++) {
                from[i] = in.nextInt() - 1;
                to[i] = in.nextInt() - 1;
            }

            int ans = 0;
            for (int i = 0; i < m; i++) {
                UnionFind uf = new UnionFind(n);
                for (int j = 0; j < m; j++) {
                    if (j == i) continue;

                    uf.union(from[j], to[j]);
                }

                if (uf.getGroups().size() > 1) ans++;
            }

            out.println(ans);
        }

    }

    static class InputReader {
        BufferedReader in;
        StringTokenizer tok;

        public String nextString() {
            while (!tok.hasMoreTokens()) {
                try {
                    tok = new StringTokenizer(in.readLine(), " ");
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
            }
            return tok.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(nextString());
        }

        public InputReader(InputStream inputStream) {
            in = new BufferedReader(new InputStreamReader(inputStream));
            tok = new StringTokenizer("");
        }

    }

    static class UnionFind {
        int[] parent;

        public UnionFind(int size) {
            parent = new int[size];
            Arrays.fill(parent, -1);
        }

        public boolean union(int x, int y) {
            x = root(x);
            y = root(y);
            if (x != y) {
                if (parent[y] < parent[x]) {
                    int tmp = y;
                    y = x;
                    x = tmp;
                }
                parent[x] += parent[y];
                parent[y] = x;
                return true;
            }
            return false;
        }

        public int root(int x) {
            return parent[x] < 0 ? x : (parent[x] = root(parent[x]));
        }

        public ArrayList<ArrayList<Integer>> getGroups() {
            int n = parent.length;
            ArrayList<ArrayList<Integer>> groups = new ArrayList<>();
            HashMap<Integer, Integer> map = new HashMap<>();
            for (int i = 0; i < n; i++) {
                int r = root(i);
                if (!map.containsKey(r)) {
                    map.put(r, groups.size());
                    groups.add(new ArrayList<>());
                }
                groups.get(map.get(r)).add(i);
            }
            return groups;
        }

    }
}



Measured memory_bytes: 23124