#include <iostream>
#include <string>

using namespace std;

int main()
{
  int ans=0;
  string a;
  cin >> a;

  for(int i=0;i<a.size();i++){
    if(a[i]!='0')ans += (int)(a[i]-'0');
    else ans += 10;
  }

  cout << ans << endl;

  return 0;
}