#sentinel-controlled repetition
#write a program that reads a sequence of valid grades (integer between 0 
#and 100. First invalid grade will terminate the input
#Program finds the number of students who passed the course and the average 
#passing grade
#IN THIS EXAMPLE WE DON"T KNOW UPFRONT HOW MANY GRADES WE WILL READ!!!!
#we only can use loop WHILE in these questions!!!
def main():
	sum_pass=0
	count_pass=0
	grade=int(input("enter valid grade, integer between 0 and 100 "))
	while(grade>=0 and grade<=100):
		if(grade>=60):
			sum_pass+=grade
			count_pass+=1
		grade=int(input("enter valid grade, integer between 0 and 100 "))
	if(count_pass>0):
		print(count_pass, sum_pass/count_pass)
	else:
		print("no passing grades")
main()