#include"bits/stdc++.h"
using namespace std;


int main() {
	string s;
	cin >> s;
	int ans=0;
	for (int i = 0; i < s.length(); i++) {
		if (s[i] >= '1'&&s[i] <= '9') {
			ans += s[i]-'0';
		}
	}
	cout << ans << endl;
}