There is a monastery. The monks in this monastery do not communicate, by speech or by sign, but are of consederable intellegence. One night, a burglar enters, and paints the noses of some of the monks green.
The next morning, the monks assemble. They can see one another, but cannot communicate whose noses are green. The abbot instructs the monks to return to their cells, and for those monks with green noses to leave the monastery.
The assemblies continue for a further six days, with none of the monks leaving. After the seventh assembly, after returning to their cells, all the green-nosed monks, independently and without communication, left the monastery.
How many monks had green noses?
Answer