#include<iostream>
#include<string>

int main() {
	std::string str;
	std::cin >> str;

	long a = 0;
	for (int i = 0; i < str.length(); i++) {
		if (str[i] >= '0' && str[i] <= '9') {
			a += str[i] - '0';
		}
	}
	std::cout << a << std::endl;
	return 0;
}