#include <bits/stdc++.h>
#define rep(i,n)for(long long i=0;i<(n);i++)
using namespace std;
typedef unsigned long long ull;
typedef long long ll;
const ll INF=1e18;
const int MOD=1e9+7;
const double pi=acos(-1);

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