#include<bits/stdc++.h>
typedef long long ll;
using namespace std;
int INF = 1LL << 30;
int MOD = 1e9+7;
main(){
    string S;
    cin >> S;
    int sum = 0;
    for(auto c:S){
        sum += c=='0'?10:(c-'0');
    }
    cout << sum << endl;
}