import sys
import heapq
input = sys.stdin.readline
N,M = map(int,input().split())
dp = [-1]*100001
stack = []
dp[N] = 0
root_dict = {}
root_dict[N] = -1
heapq.heappush(stack,(0,N))
if N == M:
print(0)
print(N)
else:
flag = False
while stack:
cnt, x = heapq.heappop(stack)
for ind,nx in enumerate([2*x,x-1,x+1]):
if 0<=nx<100001:
if dp[nx] == -1:
dp[nx] = cnt + 1
root_dict[nx] = x
heapq.heappush(stack,(cnt+1,nx))
if nx == M:
find_route = [nx]
cu_route = nx
while cu_route != N:
cu_route = root_dict[cu_route]
find_route.append(cu_route)
flag = True
print(cnt+1)
print(*reversed(find_route))
break
if flag:
break
import sys
from collections import deque
input = sys.stdin.readline
N,M = map(int,input().split())
dp = [-1]*100001
stack = deque()
dp[N] = 0
root_list = [-1]*100001
stack.append((0,N))
if N > M:
print(N-M)
print(' '.join(map(str,range(N,M-1,-1))))
elif N == M:
print(0)
print(N)
else:
flag = False
while stack:
cnt, x = stack.popleft()
for ind,nx in enumerate([2*x,x-1,x+1]):
if 0<=nx<100001:
if dp[nx] == -1:
dp[nx] = cnt + 1
root_list[nx] = x
stack.append((cnt+1,nx))
if nx == M:
find_route = [nx]
cu_route = nx
while cu_route != N:
cu_route = root_list[cu_route]
find_route.append(cu_route)
flag = True
print(cnt+1)
print(*reversed(find_route))
break
if flag:
break