#include <bits/stdc++.h>
#define REP(i,n) for(int i=0;i<(n);++i)
using namespace std;

int main () {
    string s; int sum;
    cin >> s;

    REP (i, s.size()) {
        if (s[i] == '0') sum += 10;
        else sum += s[i] - '0';
    }
    cout << sum << endl;
    return 0;
}