Hello I am fairly new to python and would like to know where my program is failing and why.. thanks, the basic coding is as follows,

```
    grade = 0
    total = 0
    scorecount = 0
    while grade >=0:
        grade = raw_input("enter grade ->")
        grade = int(grade)
        total = total + grade
        total = int(total)
        scorecount = scorecount + 1
        scorecount= int(scorecount)
    average = total/scorecount
    print average

```