Sum of Digits in String

Background

Congcong is learning string processing. He encountered an interesting problem that requires extracting and calculating the sum of all digits from a string.

Problem Description

Given a string, return the sum of the digits $0-9$ that appear in the string, ignoring all other characters. Return $0$ if there are no digits in the string.

Input Format

Input is given from Standard Input in the following format.

A single line string $S$.

Output Format

Output is printed to Standard Output in the following format.

An integer representing the sum of all digits in the string.

Sample

aa1bc2d3

6

aa11b33

8

Chocolate

0

Sample Explanation

Sample 1: The string "aa1bc2d3" contains digits '1', '2', '3'. Their sum is $1 + 2 + 3 = 6$. Sample 2: The string "aa11b33" contains digits '1', '1', '3', '3'. Their sum is $1 + 1 + 3 + 3 = 8$. Sample 3: The string "Chocolate" does not contain any digits, so the sum is $0$.

Constraints

The length of string $S$ does not exceed $1000$.