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.uniteAll(sc.nextInt() - 1, sc.nextInt() - 1); } boolean enable = true; for (int i = 0; i < n && enable; i++) { enable = uft.sameAll(i); } System.out.println(enable ? "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]); } } private boolean same(int x, int y) { return find(x) == find(y); } public boolean sameAll(int x) { return same(x, x + size); } private void unite(int x, int y) { if (!same(x, y)) { parents[find(x)] = find(y); } } public void uniteAll(int x, int y) { unite(x, y + size); unite(x + size, y); } } } 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(); } } }