#include <iostream>
//#include <vector>
//#include <algorithm>
//#include <string>
//#include <iomanip>

using namespace std;

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

	int sum = 0;
	for (unsigned int i = 0; i < S.length(); i++)
	{
		if ('1' <= S[i] && S[i] <= '9')
		{
			sum += S[i] - '0';
		}
	}

	cout << sum << endl;

	return 0;
}