#William Baker 1703131

print("Hello")

number = int(input("Enter a number (-1 exits): "))
total = 0

while(number != -1):
    total = total + number
    number = int(input("Enter another number (-1 exits): "))

    if(number < -1):
        print("You may not input negative values")
        number = 0
    
print("Total is: {0}".format(total))
print("Goodbye.")