During a certain flight, passengers are allowed to carry a carry-on luggage into the airplane as long as the weight of the luggage does not exceed 5 kilograms. Determine which of the following items a passenger should include with his/her carry-on luggage so that a maximum number of items have been included. Furthermore, if the towel is selected, then soap & shampoo should also be selected, and at least one pair of pants, at least one shirt, and at least one pair of snickers should be included in the carry-on luggage.

What is the optimal number of items that can be included with the carry-on luggage? Enter a whole number.

	item	weight (Kg)
X1	towel	0.4
X2	jacket	0.9
X3	book # 1	1
X4	book # 2	0.9
X5	underwear	0.5
X6	soap & shampoo	1.4
X7	shoes	0.8
X8	pants # 1	0.4
X9	pants # 2	0.5
X10	shirt # 1	0.3
X11	shirt # 2	0.3
X12	snickers # 1	0.5
X13	snickers # 2	0.5