#Write a program that reads 10-digit integer, and finds and prints the average of its 
#EVEN digits. If there are no even digits in the input, the program prints an 
#appropriate message. 

n = int(input("enter ONE 10-digit number "))
if(n>=1000000000 and n <=9999999999):
	i = 0
	sum = 0
	count_even=0
	while(i<10):
		digit=n%10
		if(digit%2==0):
			sum=sum+digit
			count_even=count_even+1
		i=i+1
		n = n//10
	if(count_even==0):
		print("no even digits")
	else:
		print("average of even digits",sum/count_even)
else:
	print("invalid input")