Digit sum of a transaction ID

Problem

A payments app runs a quick check on each UPI transaction ID: it adds up the digits. Print the digit sum of the given ID.

Write a method static int digitSum(long n) that returns the sum of the digits of n.

Example 1

Input

Output

4 + 0 + 7 + 2 = 13.

Example 2

Input

Output

The only digit is 0.

Try the problem first. Open one hint at a time.

Hint 1

n % 10 gives the last digit and n / 10 removes it.

Hint 2

Repeat while n > 0, adding each last digit to a total.

Write your Java code, run it on the examples and submit it to hidden tests.