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

int main() {

	string s;
	cin >> s;

	int ans=0;

	int num=0;

	for(int i =0; i<s.length(); i++){
		if(iswdigit(s[i])){

			ans += s[i]-'0';

		}
	}

	cout<<ans<<endl;
	return 0;
}