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

int main() {
	string s;
	cin >> s;

	int sum = 0;
	for (int i = 0; i < s.size(); i++) {
		char c = s.at(i);
		if (c >= '0' && c <= '9') {
			int n = c - 48;
			sum += n;
		}
	}

	cout << sum << endl;
}