#include <iostream>
#include <string>

using namespace std;

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

	int sum = 0;
	string::iterator it;

	for(it = str.begin(); it != str.end(); it++)
	{
		if('0' <= *it && *it <= '9')
			sum += *it - 48;
	}

	cout << sum << endl;

	return 0;
}