class UnionFind:
    def __init__(self, n):
        self.n = n
        self.parent_or_size = [-1] * n

    def merge(self, a, b):
        x = self.root(a)
        y = self.root(b)
        if x == y:
            return False
        if -self.parent_or_size[x] < -self.parent_or_size[y]:
            x, y = y, x
        self.parent_or_size[x] += self.parent_or_size[y]
        self.parent_or_size[y] = x
        return True

    def same(self, a, b):
        return self.root(a) == self.root(b)

    def root(self, a):
        if self.parent_or_size[a] < 0:
            return a
        self.parent_or_size[a] = self.root(self.parent_or_size[a])
        return self.parent_or_size[a]

    def size(self, a):
        return -self.parent_or_size[self.root(a)]


N, M = map(int, input().split())

uf = UnionFind(N * 2)

for _ in range(M):
    a, b = map(int, input().split())
    uf.merge(a - 1, b - 1 + N)
    uf.merge(a - 1 + N, b - 1)

for i in range(N):
    if not uf.same(i, i + N):
        print("No")
        exit()

print("Yes")