//#include <bits/stdc++.h>
#include <iostream> // cout, endl, cin
#include <string> // string, to_string, stoi
#include <vector> // vector
#include <algorithm> // min, max, swap, sort, reverse, lower_bound, upper_bound
#include <utility> // pair, make_pair
#include <tuple> // tuple, make_tuple
#include <cstdint> // int64_t, int*_t
#include <cstdio> // printf
#include <map> // map
#include <queue> // queue, priority_queue
#include <set> // set
#include <stack> // stack
#include <deque> // deque
#include <unordered_map> // unordered_map
#include <unordered_set> // unordered_set
#include <bitset> // bitset
#include <cctype> // isupper, islower, isdigit, toupper, tolower
#include <math.h>
#include <iomanip>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;

#define rep(i,n) for(int i = 0; i < (n); i++)
#define pb push_back 
#define eb emplace_back 
#define all(x) x.begin() , x.end()
#define fi first
#define se second
#define Yes() {puts("YES");return;}
#define No()  {puts("No"); return;}
#define P pair <int , int>
#define vb vector<bool>
#define vi vector<int> 
#define vll vector<ll> 
#define vvi vector<vi>

const int mod = 1000000007;
const ld PI = 3.14159265358979;
const int INF = 1001001001;
const ll LINF = (1LL << 60);
const int MX = 200005;

ll gcd (ll a , ll b) {if (a < b) swap(a , b);if (b == 0) return 1;if (a % b == 0) return b;else return gcd (b , a % b);}
bool is_2power (ll x) { if((x & (x - 1)) == 0) return true; else return false;}

bool is_prime (ll x) {
    if (x == 1) return false;
    if (x == 2 || x == 3 || x == 5 || x == 7) return true;
    if((x & 1) == 0) return false;
    for (ll i = 3; i * i <= x; i += 2) if(x % i == 0)return false;
    return true;
}

void is_prime2() {
    const int sz = 10001; //使う時は外に出す
    vb table(sz , 0); //使う時は外に出す
    for (int i = 2; i < sz; i++) {
        for(int j = 2; i * j <= sz; j++) {
            table[i * j] = true;
        }
    }
}

vector<int> divisor (ll x) {
    vector<int> ret;
    for (int i = 2; i * i <= x; i++) {
        while (x % i == 0) {
            ret.push_back(i);
            x /= i;
        }
    }
    if (x > 1) {
        ret.push_back(x);
    }
    return ret;
}

ll modpow (ll x , ll p , ll m) {
    ll ret = 1;
    while (p > 0) {
        if(p & 1)ret *= x;
        x *= x;
        x %= m;
        p >>= 1;
    }
    return ret;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(15);
    ll n;
    cin >> n;
    ll x = (ll)1e9 + 1;
    ll p = n / x;
    ll ans = min(p , (ll)9);
    vll a;
    a.pb((ll)11);
    a.pb((ll)101);
    a.pb((ll)1001);
    a.pb((ll)10001);
    a.pb((ll)100001);
    a.pb((ll)1000001);
    a.pb((ll)10000001);
    a.pb((ll)100000001);
    a.pb((ll)1000000001);
    a.pb((ll)10000000001);
    rep(i,a.size()) {
        ans += p / a[i];
        p /= a[i];
    }
    cout << ans << endl;
    return 0;
}