#include <iostream>
#include <string>
using namespace std;
int main(int argc, char* argv[])
{
	string S;
	cin>>S;
	int aw=0;
	for (int i=0;i<S.length();i++){
		if (S[i]=='0'){
			aw+=10;
		}else{
			aw+=S[i]-'0';
		}
	}
	cout<<aw<<endl;
	return 0;
}