#lab practice nov 16
def final_price(num, time):
	total=0
	for i in range(num):
		price=float(input("enter price of the item "))
		total=total+price
	if(time<=14 and total>=50):
		price_20off=total-20
		price_20percent_off=total*(1-20/100)
		if(price_20off<price_20percent_off):
			final_price=price_20off
		else:
			final_price=price_20percent_off

	else:
		final_price=total*(1-20/100)

	return final_price
		
def store_sales(n):
	total=0
	num_items=0
	for i in range(1,n+1):
		print("processing customer", i)
		items=int(input("enter num of items bought "))
		time=float(input("enter purchase time "))
		total_price=final_price(items, time)
		print("total for customer", i, "is", total_price)
		total=total+total_price
		num_items=num_items+items
	ave=total/num_items
	return total, ave

def main():
	n=int(input("enter number of customers "))
	if(n>0):
		total, ave=store_sales(n)
		print("total sales", total)
		print("ave item price ", ave)
	else:
		print("no customers came to shop")
main()