Postman delivers the mail in the small village. This village has exactly ten houses, numbered from 1 to 10.
In a certain week, he did not deliver any mail at two houses in the village but at the other houses he delivered mail three times each.
Each working day he delivered mail at exactly four houses.
The sums of the house numbers where he delivered mail were:
on Monday: 18
on Tuesday: 12
on Wednesday: 23
on Thursday: 19
on Friday: 32
on Saturday: 25
on Sunday: he never works
Which two houses didn't get any mail that week?