#include <iostream>
using namespace std;
int main(void) {
	string s;
	cin >> s;
	int sum = 0;
	for (int i = 0; i < s.size(); ++i) {
		if (48 <= s[i] && s[i] <= 57)
			sum += s[i] - '0';
	}
	cout << sum << endl;
	return 0;
}