Baekjoon-13913-숨바꼭질 4

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

queue = [N]
visited = [[-1,[]] for _ in range(int(1e5+1))] # 걸린 시간, 경우의 수
visited[N][0] = 0
visited[N][1].append(N)

while queue:
    pos = queue.pop(0)

    for i in [pos+1, pos-1, 2*pos]:
        if 0 <= i <= int(1e5):
            if visited[i][0] == -1:
                visited[i][0] = visited[pos][0] + 1
                visited[i][1] = pos
                queue.append(i)

print(visited[K][0])

# path
path = [K]
while path[-1]!=N:
    path.append(visited[path[-1]][1])
path.reverse()
print(*path, sep=' ')