K=int(input())
prime=[True for _ in range(1000001)]
prime[0]=False
prime[1]=False

for i in range(2,1000001):
  if prime[i]:
    cnt=2
    while i*cnt<1000001:
      prime[i*cnt]=False
      cnt+=1

ans2=0
ansp=0
for i in range(1,250):
  for j in range(1,250):
    if i*j==K and i+j<=250:
      ans2=i
      ansp=j
ans=[2]*ans2

for i in range(999999):
  if ansp==0:
    break
  if prime[i] and prime[i+2]:
    ans.append(i)
    ansp-=1

print(len(ans))
print(*ans)