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

p = [-1]*(2*n+10)
def find(x):
  if p[x] < 0:
    return x
  else:
    p[x] = find(p[x])
    return p[x]
def union(x,y):
  x = find(x)
  y = find(y)
  if x == y:
    return
  if p[x] > p[y]:
    x,y = y,x
  p[x] += p[y]
  p[y] = x


graph = [[] for i in range(n+1)]
for i in range(m):
  a,b = map(int,input().split())
  union(a, b+n)
  union(a+n, b)

ans = 1
for i in range(1,n+1):
  ans &= find(i) == find(i+n)

print('Yes') if ans else print('No')