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

int main() {
    string S;
    cin >> S;

    int ans = 0;
    rep(i,S.size()){
        if(S[i]=='0')
            ans += 10;
        else
            ans += (S[i] - '0');
    }

    cout << ans << endl;

    return 0;
}