#include <iostream>
#include <string>
using namespace std;

int main() {
	// your code goes here
	string s;
	int ans = 0;
	cin >>s;
	for(int i = 0;i < s.size();i++){
		if('0'<=s[i]&&s[i]<='9'){
			ans +=(int)s[i] - '0';
		}
	}
	cout <<ans <<endl;
	return 0;
}