#include <iostream>
#include <string>

int main(void){
	int count=0;
	std::string S;
	std::cin >> S;
	for (int i = 0; i < S.length(); i++){
		if (S[i] - '0' == 0)count += 10;
		else count += S[i] - '0';
	}
	std::cout << count<<std::endl;
	return 0;
}