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);
        while (m-- > 0) {
            uft.unite(sc.nextInt() - 1, sc.nextInt() - 1);
        }
        System.out.println(uft.isMatch() ? "Yes" : "No");
    }
    
    static class UnionFindTree {
        int size;
        int[] parents;
        
        public UnionFindTree(int size) {
            this.size = size;
            parents = new int[size * 2];
            for (int i = 0; i < size * 2; i++) {
                parents[i] = i;
            }
        }
        
        public int find(int x) {
            if (x == parents[x]) {
                return x;
            } else {
                return parents[x] = find(parents[x]);
            }
        }
        
        public boolean same(int x, int y) {
            return find(x) == find(y);
        }
        
        public void unite(int x, int y) {
            if (!same(x + size, y)) {
                parents[find(x + size)] = find(y);
            }
            if (!same(x, y + size)) {
                parents[find(x)] = find(y + size);
            }
        }
        
        public boolean isMatch() {
            for (int i = 0; i < size; i++) {
                if (same(i, i + size)) {
                    return false;
                }
            }
            return true;
        }
    }
}
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();
        }
    }
    
}