import java.io.File;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;

public class BridgeNum {
    public static void main(String[] args) throws IOException {
       // Scanner in = new Scanner(System.in);
        List<String> lines = Files.readAllLines(Paths.get("11.txt"), Charset.defaultCharset());
        int n = Integer.parseInt(lines.get(0));
        int m = Integer.parseInt(lines.get(1));
        ArrayList<ArrayList<Integer>> ribs = new ArrayList<>();
        int[] count = new int[1];
        int[][] len = new int[n][2];
        int[] helper = new int[n];
        Arrays.fill(helper, -1);
        Arrays.fill(count, 0);
        for (int i = 0; i < n; i++){
            ArrayList<Integer> arr= new ArrayList<>();
            ribs.add(arr);
        }
        for (int i = 0;i < m;i++){
            String s = lines.get(i + 2);
            String str = "";
            int j = 0;
            while (s.charAt(j) != ' ') {
                str += s.charAt(j);
                j++;
            }
            int u = Integer.parseInt(str);
            j = 0;
            str = "";
            while (s.charAt(j) != ' ') {
                str += s.charAt(j);
                j++;
            }
            int v = Integer.parseInt(str);
            ribs.get(v).add(u);
            ribs.get(u).add(v);
        }
        for (int i = 0; i < n; i++){
            if (helper[i] == -1) dfs(i, -1, 0, count, helper, ribs, n, len);
        }
        System.out.println(count[0]);
    }

    public static void dfs(int i, int e, int k, int[] count, int[] helper, ArrayList<ArrayList<Integer>> ribs, int n, int[][] len){
        helper[i] = 0;
        len[i][0] = len[i][1] = k++;
        int j = -1;
        while (++j < ribs.get(i).size()){
            int v = ribs.get(i).get(j);
            if (v == e) continue;
            if(helper[v] != -1) len[i][1] = Math.min(len[i][1], len[v][0]);
            else {
                dfs(v, i, k, count, helper, ribs, n, len);
                len[i][1] = Math.min(len[i][1], len[v][1]);
                if(len[v][1] > len[i][0]) ++count[0];
            }
        }
    }
}