#include <iostream>
#include <string>

using namespace std;
int main()
{
	string str;
	cin >> str;
	int a = 0;
	for (unsigned int i = 0; i < str.length(); i++)
	{
		if (str[i] >= '0' && str[i] <= '9')
		{
			a += str[i] - '0';
		}
	}

	cout << a << endl;
	return 0;
}