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

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

	int sum = 0;
	for (auto i = str.begin(); i != str.end() ; i++)
	{
		if ((*i >= '0') && (*i <= '9'))
		{
			sum += *i - 48;
		}
	}
	cout << sum << endl;

	return 0;
}