import java.io.BufferedReader
import java.io.InputStream
import java.io.InputStreamReader
import java.lang.AssertionError
import java.util.*
import kotlin.math.abs
import kotlin.math.max
import kotlin.math.min

val MOD = 1_000_000_007
//val MOD = 998244353
class UnionFind(n: Int) {
  private val par = IntArray(n){it}
  private val rank = IntArray(n){1} // 集合の要素数
  private val visits = IntArray(n) // 訪れた場所をfind毎に用意するのがもったいないのでつかいまわす

  fun find(x: Int): Int {
    var ptr = 0
    var i = x
    while(par[i] != i) {
      visits[ptr++] = i
      i = par[i]
    }

    for (j in 0 until ptr) {
      par[visits[j]] = i
    }
    return i
  }

  private fun merge(node: Int, rt: Int): Int {
    par[node] = rt
    rank[rt] += rank[node]
    return rt
  }

  fun unite(x: Int, y: Int): Boolean {
    val x1 = find(x)
    val y1 = find(y)
    return if (x1 == y1) false
    else {
      if (rank[x1] < rank[y1])
        merge(x1, y1)
      else
        merge(y1, x1)

      true
    }
  }

  fun isSame(x: Int, y: Int) = find(x) == find(y)

  fun isRoot(x: Int) = par[x] == x

  /**
   * xを解決する必要がないときは直にrankをみる
   */
  fun cntNodes(x: Int): Int = rank[find(x)]

  fun inspect() = run{par}
}
fun testBipartite(N: Int, g: Array<IntArray>, D: IntArray): Boolean {
  for (v in 0 until N) {
    for (i in g[v].indices) {
      val u = g[v][i]
      if (D[u] % 2 == D[v] % 2) {
        return false
      }
    }
  }

  return true
}
fun packUGraph(n: Int, E: List<Pair<Int, Int>>): Array<IntArray> {
  val p = IntArray(n)
  val m = E.size
  for (i in 0 until m) {
    ++p[E[i].first]
    ++p[E[i].second]
  }
  val g = Array(n){IntArray(p[it])}
  for (i in 0 until m) {
    g[E[i].first][--p[E[i].first]] = E[i].second
    g[E[i].second][--p[E[i].second]] = E[i].first
  }
  return g
}
/**
 * (dist, parent, queue)
 * 有効グラフでは使わないように注意
 * @param rt ルートノードを指定する。nullの場合は全ノード辿るまで繰り返す
 */
fun traceBfs(g: Array<IntArray>, rt: Int? = 0): Array<IntArray> {
  val n = g.size
  val q = IntArray(n)
  val d = IntArray(n)
  val p = IntArray(n){-2}
  var h = 0
  var t = 0

  fun bfs(rt: Int) {
    p[rt] = -1
    q[t++] = rt
    d[rt] = 0
    while (h < t) {
      val v = q[h++]
      for (i in g[v].indices) { // List<Int>に変更したときこちらの方法でないとiterator生成して遅くなる
        val u = g[v][i]
        if (p[u] == -2) {
          p[u] = v
          q[t++] = u
          d[u] = d[v] + 1
        }
      }
    }
  }

  if (rt != null) {
    bfs(rt)
  } else {
    for (v in 0 until n) {
      if (p[v] != -2) continue
      bfs(v)
    }
  }
  return arrayOf(d, p, q)
}
class Solver(stream: InputStream, private val out: java.io.PrintWriter) {
  private val reader = BufferedReader(InputStreamReader(stream), 32768)

  fun solve() {
    val (N, M) = na(2)
    val (from, to) = na2(M, -1)
    val uf = UnionFind(N)
    for (i in 0 until M) {
      uf.unite(from[i], to[i])
    }

    val map = IntArray(N)
    val grpSize = IntArray(N)
    for (v in 0 until N) {
      val id = uf.find(v)
      map[v] = grpSize[id]++
    }
    
    val edges = Array(N){ mutableListOf<Pair<Int, Int>>()}
    for (i in 0 until M) {
      edges[uf.find(from[i])].add(Pair(map[from[i]], map[to[i]]))
    }

    var ok = true
    for (i in 0 until N) {
      val n = grpSize[i]
      if (n == 0) continue
      val g = packUGraph(n, edges[i])
      val (D, _, _) = traceBfs(g)
      ok = ok && !testBipartite(n, g, D)
    }
    out.println(if (ok) "Yes" else "No")
  }













































  private val isDebug = try {
    // なんか本番でエラーでる
    System.getenv("MY_DEBUG") != null
  } catch (t: Throwable) {
    false
  }

  private var tokenizer: StringTokenizer? = null
  private fun next(): String {
    while (tokenizer == null || !tokenizer!!.hasMoreTokens()) {
      tokenizer = StringTokenizer(reader.readLine())
    }
    return tokenizer!!.nextToken()
  }

  private fun ni() = next().toInt()
  private fun nl() = next().toLong()
  private fun ns() = next()
  private fun na(n: Int, offset: Int = 0): IntArray {
    return IntArray(n) { ni() + offset }
  }
  private fun nal(n: Int, offset: Int = 0): LongArray {
    val res = LongArray(n)
    for (i in 0 until n) {
      res[i] = nl() + offset
    }
    return res
  }

  private fun na2(n: Int, offset: Int = 0): Array<IntArray> {
    val a  = Array(2){IntArray(n)}
    for (i in 0 until n) {
      for (e in a) {
        e[i] = ni() + offset
      }
    }
    return a
  }

  private inline fun debug(msg: () -> String) {
    if (isDebug) System.err.println(msg())
  }

  /**
   * コーナーケースでエラー出たりするので、debug(dp[1])のように添え字付きの場合はdebug{}をつかうこと
   */
  private inline fun debug(a: LongArray) {
    debug { a.joinToString(" ") }
  }

  private inline fun debug(a: IntArray) {
    debug { a.joinToString(" ") }
  }

  private inline fun debug(a: BooleanArray) {
    debug { toString(a) }
  }

  private inline fun toString(a: BooleanArray) = run{a.map { if (it) 1 else 0 }.joinToString("")}

  private inline fun debugDim(A: Array<LongArray>) {
    if (isDebug) {
      for (a in A) {
        debug(a)
      }
    }
  }
  private inline fun debugDim(A: Array<IntArray>) {
    if (isDebug) {
      for (a in A) {
        debug(a)
      }
    }
  }
  private inline fun debugDim(A: Array<BooleanArray>) {
    if (isDebug) {
      for (a in A) {
        debug(a)
      }
    }
  }

  /**
   * 勝手にimport消されるのを防ぎたい
   */
  private fun hoge() {
    min(1, 2)
    max(1, 2)
    abs(-10)
  }

  private inline fun assert(b: Boolean) = run{if (!b) throw AssertionError()}
  private inline fun assert(b: Boolean, f: () -> String) = run{if (!b) throw AssertionError(f())}

  companion object {
    // TestRunnerから呼びたいので単純なmainじゃだめ
    fun main() {
//      val out = java.io.PrintWriter(FileOutputStream("./out.txt"))
      val out = java.io.PrintWriter(System.out)
      Solver(System.`in`, out).solve()
      out.flush()
    }
  }
}

/**
 * judgeから呼ばれる
 */
fun main() = Solver.main()