#from sys import stdin
#input = lambda :stdin.readline()[:-1]

n,m = map(int, input().split())

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

ans = "Yes"
memo = [-1 for _ in range(n)]
for i in range(n):
    if memo[i] != -1:
        continue
    d = [i]
    memo[i] = 0
    while d:
        j = d.pop()
        for k in path[j]:
            if memo[k] == -1:
                memo[k] = memo[j] ^ 1
                d.append(k)
            elif memo[k] == memo[j]:
                ans = "No"
print(ans)