n,m = map(int,input().split())
G = [[] for i in range(n)]
for i in range(m):
	a,b = map(int,input().split())
	a -= 1
	b -= 1
	G[a].append(b)
	G[b].append(a)

ans = 'Yes'
C = [-1 for i in range(N)]
for s in range(N):
	if C[s] != -1:
		continue
	C[s] = 0
	todo = [s]
	while len(todo):
		s = todo.pop()
		for t in G[s]:
			if C[t] == -1:
				C[t] = C[s] ^ 1
				todo.append(t)
			else:
				if C[s] == C[t]:
					print('No')
					exit()
print(ans)