total=0
num1=int(input("Enter number: (-1 to exit)"))
while (num1>-1):
    num2=int(input("Enter number: (-1 to exit"))
    total=num1+num2
    num1=int(input("Enter number: (-1 to exit)"))
else:
    print("Your total is:{0}".format(total))

    print("Goodbye")