#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i<(n); ++i)
using namespace std;
using ll=long long;
int main(){
    string s;
    cin>>s;
    int ans=0,sl=s.length();
    rep(i,sl){
        if(s[i]=='0'){
            ans+=10;
        }
        else{
            ans+=(s[i]-'0');
        }
    }
    cout<<ans<<endl;
}