class UnionFind:
    def __init__(self, n):
        self.data = [-1] * (n + 1)
        self.nexts = [-1] * (n + 1) # 次の要素(なければ-1)
        self.tails = list(range(n + 1)) # 末尾の要素

    def root(self, a: int) -> int:
        if self.data[a] < 0: return a
        self.data[a] = self.root(self.data[a])
        return self.data[a]

    def unite(self, a: int, b: int) -> bool:
        pa = self.root(a)
        pb = self.root(b)
        if pa == pb: return False
        if self.data[pa] > self.data[pb]:
            pa, pb = pb, pa
        self.data[pa] += self.data[pb] # pa を pb をつなげる
        self.data[pb] = pa
        # pa の末尾に pb を繋げる
        self.nexts[self.tails[pa]] = pb
        self.tails[pa] = self.tails[pb]
        return True

    def issame(self, a: int, b: int) -> bool:
        return self.root(a) == self.root(b)

    def size(self, a: int) -> int:
        """a が属する集合のサイズ"""
        return -self.data[self.root(a)]

    def group(self, a):
        """a が属する集合"""
        v = self.root(a)
        while v != -1:
            yield v
            v = self.nexts[v]


N, M = map(int, input().split())
uf = UnionFind(N * 2 + 10)
for _ in range(M):
    A, B = map(int, input().split())
    uf.unite(A, B + N)
    uf.unite(A + N, B)


for i in range(1, N+1):
    if not uf.issame(i, i+N):
        print('No')
        break
else:
    print('Yes')