import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.List;
import java.util.Queue;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] sa = br.readLine().split(" ");
		int n = Integer.parseInt(sa[0]);
		int m = Integer.parseInt(sa[1]);
		Node2[] arr = new Node2[n];
		for (int i = 0; i < n; i++) {
			Node2 o = new Node2();
			arr[i] = o;
		}
		for (int i = 0; i < m; i++) {
			sa = br.readLine().split(" ");
			int a = Integer.parseInt(sa[0]) - 1;
			int b = Integer.parseInt(sa[1]) - 1;
			arr[a].nexts.add(b);
			arr[b].nexts.add(a);
		}
		br.close();

		Queue<Integer> que = new ArrayDeque<>();
		for (int i = 0; i < n; i++) {
			if (arr[i].grp == 0) {
				que.add(i);
				arr[i].grp = 1;
				while (!que.isEmpty()) {
					int cur = que.poll();
					for (int next : arr[cur].nexts) {
						if (arr[next].grp == 0) {
							que.add(next);
							arr[next].grp = 3 - arr[cur].grp;
						} else if (arr[next].grp == arr[cur].grp) {
							System.out.println("No");
							return;
						}
					}
				}
			}
		}
		System.out.println("Yes");
	}

	static class Node2 {
		int grp;
		Integer target;
		List<Integer> nexts = new ArrayList<>();
	}
}