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

int main() {
	int sum = 0;
	string s;
	cin >> s;

	for (int i = 0; i < (int)s.size(); i++) {
		if ('0' <= s[i] && s[i] <= '9')
			sum += s[i] - '0';
	}
	cout << sum << endl;
}