#include <iostream>
#include <string>
using namespace std;
int main()
{
	string in;
	int sum;
	sum = 0;

	cin >> in;

	for (char x:in)
	{
		if (isdigit(x) != 0)
		{
			sum += (int)x-48;
			//cout << sum << "\n";
		}
	}
	cout << sum << "\n";
	return 0;
}