#include<iostream>
#include<string>
int main()
{
	std::string s;

	std::cin >> s;

	int i = 0;
	for (const char c : s)
	{
		if (c >= '0' && c <= '9')
		{
			i += c - '0';
		}
	}
	std::cout << i << std::endl;
}