package yukicoder;

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) {
		BufferedReader buff = new BufferedReader(new InputStreamReader(System.in));

		try {
			int count = 0;

			String S = buff.readLine();
			for(int i = 0; i < S.length(); ++i){
				if(S.charAt(i) >= '0' && S.charAt(i) <= '9'){
					count += Character.getNumericValue(S.charAt(i));
				}
			}

			System.out.println(count);
		} catch (Exception e) {
			e.getStackTrace();
		}
	}
}