print("___________________________________________")
print("Program to print sum of all digits")
print("___________________________________________")
try:
    n=int(input("Enter the number "))
    if(n<=0):
        print("Please enter a positive number")
    else:
        sum=0
        temp=n
        while n>0:
            r=n%10
            sum=sum+r
            n=n//10
        print("Sum of all digits in",temp,"is",sum)
except ValueError:
    print("Enter valid number")
print("___________________________________________")

kodingwindow@kw:~$ python3 kw.py
___________________________________________
Program to print sum of all digits
___________________________________________
Enter the number 123456789
Sum of all digits in 123456789 is 45
___________________________________________