import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int m = sc.nextInt();
        int[] counts = new int[n];
        for (int i = 0; i < m; i++) {
            counts[sc.nextInt()]++;
            counts[sc.nextInt()]++;
        }
        int odd = 0;
        for (int x : counts) {
            if (x % 2 == 1) {
                odd++;
            }
        }
        if (odd > 2) {
            System.out.println("NO");
        } else {
            System.out.println("YES");
        }
    }
}

class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}