#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
  string S;
  cin>>S;
  int ans = 0;
  for(int i=0;i<S.size();i++){
      if(S[i] == '0') ans += 10;
      else ans += S[i]-'0';
  }
  cout<<ans<<endl;
}