Sum Digits

Sum Digits
Write a program that reads a four-digit number and displays the sum of its digits

1213 => 1 + 2 + 1 + 3 = 7
2346 => 2 + 3 + 4 + 6 = 15
Input
On the first line, you will receive the four-digit number N
Output
On the only line of output, print the sum of digits
Constraints
1000 <= N <= 9999
Input
2346
Output
15

import java.util.Scanner;

public class sumDigits {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = Integer.parseInt(scanner.nextLine());
        System.out.println(sum(n));
    }

    public static int sum(int n) {
        if (n == 0) {
            return 0;
        }
        return n % 10 + sum(n / 10);
    }
}