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

E=[[] for i in range(n+1)]

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

DP=[-1]*(n+1)

for i in range(n+1):
    if DP[i]==-1:
        DP[i]=0
        Q=[i]
        while Q:
            x=Q.pop()
            for to in E[x]:
                if DP[to]==DP[x]:
                    print("No")
                    exit()
                elif DP[to]==-1:
                    DP[to]=DP[x]^1
                    Q.append(to)

print("Yes")