# Compute average of a set of grades

# Write a function average_grade that does not take any parameters,
# and computes the average of a set of grades

# A user should be allowed to type any number of grades
# The user should type -1 to indicate that she/he is done
# entering the grades

# The function should just return the average grade

def average_grade():
    count = 0
    asum = 0
    grade = int(raw_input("Please next grade, -1 to quit"))

    while grade != -1:
        count += 1
        asum += grade
        grade = int(raw_input("Please next grade, -1 to quit"))

    if count > 0:
        return asum / float(count) #every time you divide
                                    #think what IF denominator = 0....
    return 0