#include <iostream>
#include <vector>
#include <map>
#include <queue>
#include <string>
#include <set>
#include <algorithm>
#include <list>
using namespace std;
using ll = long long int;

int main(){
    string s;
    cin >> s;
    ll answ = 0;
    if(s.size() > 1){
        ll sum = 0;
        for(ll i = 0; i < s.size(); ++i){
            sum += atoi(s.substr(i,1).c_str());
        }
        answ = sum + ((s.size() - 1) * (s.size())) * 9 / 2;
        cout << answ << endl;
    }
    else{
        cout << atoi(s.c_str()) << endl;
    }
    return 0;
}