#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define int long long
using namespace std;

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;
}