from collections import deque
N,M = map(int,input().split())
G = {i:[] for i in range(1,N+1)}
for _ in range(M):
    a,b = map(int,input().split())
    G[a].append(b)
    G[b].append(a)
col = [set() for _ in range(N+1)]
for i in range(1,N+1):
    if len(col[i])!=0:continue
    col[i].add(0)
    que = deque([i])
    while que:
        x = que.popleft()
        if len(col[x])==1:
            s = list(col[x])[0]
            for y in G[x]:
                if 1-s not in col[y]:
                    col[y].add(1-s)
                    que.append(y)
        elif len(col[x])==2:
            for y in G[x]:
                if len(col[y])==1:
                    col[y] = set([0,1])
                    que.append(y)
flag = "Yes"
for i in range(1,N+1):
    if len(col[i])<2:
        flag = "No"
        break
print(flag)