import java.util.Scanner;

public class Yuki289 {
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		String str = scan.next();
		char[] beforeOmitCharArr = str.toCharArray();
		int total = 0;

		for(int i = 0; i < beforeOmitCharArr.length; i++){
			if(isNum((beforeOmitCharArr[i]))){
				total = total + Character.getNumericValue(beforeOmitCharArr[i]);
			}
		}

		System.out.println(total);
	}

	//正直クソコード
	static boolean isNum(char ch) {
		if(ch == '0' || ch == '1' || ch == '2' || ch == '3' || ch == '4' || ch == '5'||
		   ch == '6' || ch == '7' || ch == '8' || ch == '9'){
			return true;
		}else{
			return false;
		}

	}
}