```
class Solution(object):
def findDisappearedNumbers(self, nums):
for k in range(3):
for i, num in enumerate(nums):
if i + 1 != num:
nums[num - 1], nums[i] = nums[i], nums[num - 1]
return [i + 1 for i, num in enumerate(nums) if i + 1 != num]
```