#include <iostream>
#include <string>

using namespace std;
typedef long long int lint;

bool digitQ(char ch) {
	ch -= '0';
	if (0 <= ch && ch < 10) return true;
	return false;
}

int main()
{
	string str;
	cin >> str;
	
	lint sum = 0;
	for (int i = 0; i < str.size(); i++)
		if (digitQ(str[i]))
			sum += str[i] - '0';

	cout << sum << endl;

	return 0;
}