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

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