import sys
sys.setrecursionlimit(10 ** 8)

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

C = 2 * N
parent = [-1] * C
def find(i):
    if parent[i] < 0:return i
    parent[i] = find(parent[i])
    return parent[i]
def unite(i,j):
    I = find(i)
    J = find(j)
    if I == J:return False
    if parent[I] < parent[J]:
        I,J = J,I
    parent[J] += parent[I]
    parent[I] = J
    return True
def isSame(i,j):
    return find(i) == find(j)
for _ in range(M):
    a,b = map(int,input().split())
    a -= 1
    b -= 1
    unite(a,b + N)
    unite(a + N,b)
for i in range(N):
    if find(i) != find(i + N):
        print('No')
        exit()
print('Yes')