easy

Sum=0
p=[]
a,b=input().split()
a=int(a)
b=int(b)
for i in range(a,b):
    if i%4==0 and i%100 != 0:
        Sum+=1
        p.append(i)
    elif i%100==0 and i%400==0:
        Sum+=1
        p.append(i)
print(len(p))
for s in p:
    print(s,end=' ')