#Top-Down Design 

#write a function F_to_C that has one parameter Fahrenheit temperature for ONE day 
#and function returns corresponding  Celsius

#write a function average_Celsius that has one parameter - num_days - number of 
#days. This function reads Fahrenheit for each day, convert to Celsius using 
#function F_to_C and finds and returns an average Celsius

#write main that reads number of days and fids average Celsius
#use the formula Celsius = (5/9)*(Fahrenheit-32)
def F_to_C(F):
	return (5/9)*(F-32)
def average_Celsius(num_days):
	total=0
	for i in range(num_days):
		F=float(input("enter Fahrenheit "))
		C=F_to_C(F)
		print("Celsius is", C)
		total=total+C
	return total/num_days
def main():
	num_days=int(input("enter number of days "))
	if(num_days>0):
		average=average_Celsius(num_days)
		print("average Celsius is", average)
	else:
		print("invalid input")
main()