import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;

public class BridgeNum {
    public static ArrayList<ArrayList<Integer>> ribs = new ArrayList<>();
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int m = in.nextInt();
        int[] count = new int[1];
        int[] parents = new int[n];
        int[] len = new int[n];
        int[] nowLen = new int[n];
        Arrays.fill(parents, -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++){
            int v = in.nextInt();
            int u = in.nextInt();
            ribs.get(v).add(u);
            ribs.get(u).add(v);
        }
        int[] helper = new int[n];
        Arrays.fill(helper, -1);
        Thread t=new Thread(null,null,"Main",2 << 23){
            public void run(){
                for (int i = 0; i < n; i++){
                    if (helper[i] == -1) dfs(i, 1, count, helper, len, nowLen, parents);
                }
                System.out.println(count[0]);
            }
        };
        t.start();
    }


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