# 頂点倍化

N, M = map(int, input().split())
edges = [[] for i in range(N*2+1)]
for i in range(M):
    a, b = map(int, input().split())
    edges[a].append(b+N)
    edges[b+N].append(a)
    edges[b].append(a+N)
    edges[a+N].append(b)

from collections import deque
def bfs(start, goal):
    que = deque()
    que.append(start)
    visited = [0]*(N*2+1)
    visited[start] = 0
    while que:
        current = que.popleft()
        if current == goal:
            return 1
        for nxt in edges[current]:
            if visited[nxt] == 0:
                visited[nxt] = 1
                que.append(nxt)
    return 0
    
test = 1
for i in range(1, N+1):
    calc = bfs(i, i+N)
    #print(i, calc)
    test *= calc
    if test == 0:
        break
if test == 1:
    print('Yes')
else:
    print('No')