#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <set>
using namespace std;

int main(){
	string s;
	cin >> s;
	int ans = 0;
	for(auto c:s){
		if('0' <= c && c<='9'){
			ans += c-'0';
		}
	}
	cout << ans << endl;
	return 0;
}