teacher_code_python/开关灯.py

list=[0]
count=0
n=int(input())

for i in range(n):
    list.append(0)

for i in range(2,n+1):
    for j in range(i,n+1,i):
        if j%i==0:
            if list[j]==0:
                list[j]=1
            else:
                list[j]=0
        count+=1
        print(count)

for i in range(1,n+1):
    if list[i]==0:
        print(i,end=" ")