import java.io.*;
import java.util.*;
import java.util.function.*;
import java.util.stream.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int m = sc.nextInt();
        UnionFindTree uft = new UnionFindTree(n * 2);
        while (m-- > 0) {
            uft.unite(sc.nextInt() - 1, sc.nextInt() - 1);
        }
        int ans = 0;
        for (int x : uft.getCounts()) {
            ans += x % 2;
        }
        System.out.println(ans / 2);
    }
    
    static class UnionFindTree {
        int[] parents;
        int[] counts;
        
        public UnionFindTree(int size) {
            parents = IntStream.range(0, size).toArray();
            counts = IntStream.range(0, size).map(i -> 1).toArray();
        }
        
        public int find(int x) {
            return x == parents[x] ? x : (parents[x] = find(parents[x]));
        }
        
        public boolean same(int x, int y) {
            return find(x) == find(y);
        }
        
        public void unite(int x, int y) {
            int xx = find(x);
            int yy = find(y);
            if (xx != yy) {
                parents[xx] = yy;
                counts[yy] += counts[xx];
            }
        }
        
        public List<Integer> getCounts() {
            return IntStream.range(0, parents.length)
                .filter(i -> parents[i] == i)
                .map(i -> counts[i])
                .boxed()
                .toList();
        }
    }
}
class Scanner {
    BufferedReader br;
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() {
        try {
            br = new BufferedReader(new InputStreamReader(System.in));
        } catch (Exception e) {
            
        }
    }
    
    public int nextInt() {
        return Integer.parseInt(next());
    }
    
    public long nextLong() {
        return Long.parseLong(next());
    }
    
    public double nextDouble() {
        return Double.parseDouble(next());
    }
    
    public String next() {
        try {
            while (!st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            return st.nextToken();
        }
    }
    
}