import sys
sys.setrecursionlimit(1 << 25)

def main():
    import sys
    input = sys.stdin.read
    data = input().split()
    idx = 0
    N = int(data[idx])
    idx +=1
    M = int(data[idx])
    idx +=1
    
    parent = [i for i in range(2 * N + 1)]  # 1-based to 2N
    
    def find(u):
        while parent[u] != u:
            parent[u] = parent[parent[u]]
            u = parent[u]
        return u
    
    def union(u, v):
        u_root = find(u)
        v_root = find(v)
        if u_root == v_root:
            return
        parent[v_root] = u_root
    
    for _ in range(M):
        A = int(data[idx])
        idx +=1
        B = int(data[idx])
        idx +=1
        uA = A
        dA = A + N
        uB = B
        dB = B + N
        union(uA, dB)
        union(dA, uB)
    
    # Check for all 1..N stations
    for i in range(1, N+1):
        if find(i) != find(i + N):
            print("No")
            return
    print("Yes")

if __name__ == '__main__':
    main()