N, M = map(int, input().split())
li = [0]*N
for i in range(M):
    Sa, Sb = map(int, input().split())
    li[Sa] += 1
    li[Sb] += 1

if [x%2 for x in li].count(1) in [0, 2]:
    print('YES')
else:
    print('NO')