#include<bits/stdc++.h>
#define REP(i,n) for(int i=0;i<(n);i++)
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define ALL(v) (v).begin(),(v).end()
#define int long long
#define INF 1e18
using namespace std;

//-----------------------------------------------------------------------

signed main()
{
    string s; cin>>s;
    int ans=0;
    REP(i,s.size()){
        if(s[i]=='0') ans+=10;
        else ans+=s[i]-'0';
    }
    cout<<ans<<endl;
 
}