#include <iostream>
#include <vector>
#include <algorithm>
#include <string>

#define REP(i, a, b) for (int i = int(a); i < int(b); i++)
#define dump(val) cerr << __LINE__ << ":\t" << #val << " = " << (val) << endl

using namespace std;

typedef long long int lli;

int main() {
    string s;
    cin >> s;
    int ans = 0;
    for (char &c : s) {
        ans += (c == '0' ? 10 : c - '0');
    }
    cout << ans << endl;
    return 0;
}