#include <fstream>
#include <iostream>
#include <string>

int main() {

	//std::ifstream inf("Text.txt");	std::cin.rdbuf(inf.rdbuf());
	std::string S;
	std::cin >> S;

	int ans = 0;
	
	for (unsigned int i = 0; i < S.length(); i++) {
		if (S[i] == '0') {
			ans += 10;
		}
		else {
			ans += S[i] - '0';
		}
	}

	std::cout << ans << std::endl;

	return 0;
}