#include<bits/stdc++.h>
using namespace std;
using Int = long long;
//INSERT ABOVE HERE
signed main(){
  string s;
  cin>>s;
  Int x=0;
  for(Int i=0;i<(Int)s.size();i++){
    if(s[i]=='0') x+=10;
    x+=(s[i]-'0');
  }
  cout<<x<<endl;
  return 0;
}