#include <bits/stdc++.h>
using namespace std;

int main()
{
    cin.tie(0);
    iostream::sync_with_stdio(0);
    
    string s;
    cin >> s;
    
    if(s.size() == 1){
        cout << s << "\n";
        return 0;
    }
    
    long long ki = 0;
    long long sum;
    for(char c : s){
        ki += c-'0';
    }
    int hossz = s.size()-1;
        
    while(hossz > 0){
        sum = 9*hossz;
        ki += sum;
        hossz--;
    }
    
    cout << ki << "\n";
    
    return 0;
}