new file:   prob1.py
	new file:   prob10.py
	new file:   prob11.py
	new file:   prob12.py
	new file:   prob13.py
	new file:   prob14.py
	new file:   prob15.py
	new file:   prob16.py
	new file:   prob17.py
	new file:   prob18.py
	new file:   prob19.py
	new file:   prob2.py
	new file:   prob20.py
	new file:   prob3.py
	new file:   prob4.py
	new file:   prob5.py
	new file:   prob6.py
	new file:   prob7.py
	new file:   prob8.py
	new file:   prob9.py