#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <map>
#include <queue>
#include <cmath>
#include <stack>
#include <cstdio>

int main (void){
	std::string s;

	std::cin >> s;

	int result = 0;
	for (size_t i = 0; i < s.length(); i++)
	{
		if (s[i] == '0') {
			result += 10;
		}
		else {
			result += s[i] - '0';
		}
	}

	std::cout << result << std::endl;
	return 0;
}