def main():
check = input("Are you a new student(yes/no): ")
if check == "yes":
pass
elif check == "no":
totalMarks = 0
numOfSub = 0
while True:
marks = input( 'Marks for subject ' + str(numOfSub +1) + ": ")
if marks == '':
break
marks = float(marks)
if marks < 0 or marks >100:
print("Invalid marks")
continue
numOfSub = numOfSub+1
totalMarks = totalMarks + marks
percentage = totalMarks/numOfSub
print("Total marks: ", totalMarks)
print("Number of Subject is: ", numOfSub)
print("Percentage: ", round(percentage,2))
else:
print("enter a valid response")
main()