#include <bits/stdc++.h>
using namespace std;
const int inf = 1000000007;
const long long linf = 1LL << 62;
const unsigned long long ulinf = 1ULL << 63;
const double eps = 0.000001;
const double pi = 3.14159265358979323846;
template <class T>
T abs(T a) {
  return a >= 0 ? a : -a;
}
template <class T>
T sqr(T a) {
  return a * a;
}
template <class T>
T gcd(T a, T b) {
  return b ? gcd(b, a % b) : a;
}
template <class T>
T mod(T a, T b) {
  return (a % b + b) % b;
}
template <class T>
T addmod(T a, T b, T c) {
  return (T)mod((long long)a + b, (long long)c);
}
template <class T>
T mulmod(T a, T b, T c) {
  return (T)mod((long long)a * b, (long long)c);
}
template <class T>
T powmod(T a, T b, T c) {
  return (T)mod(
      b ? mulmod(mod(sqr((long long)powmod(a, b >> 1, c)), (long long)c),
                 (b & 1LL) ? a : 1LL, (long long)c)
        : 1LL,
      (long long)c);
}
template <class T>
void maxe(T &a, T b) {
  a = max(a, b);
}
template <class T>
void mine(T &a, T b) {
  a = min(a, b);
}
template <class T>
void mode(T &a, T b) {
  a = mod(a, b);
}
template <class T>
void addmode(T &a, T b, T c) {
  a = addmod(a, b, c);
}
template <class T>
void mulmode(T &a, T b, T c) {
  a = mulmod(a, b, c);
}
template <class T>
void powmode(T &a, T b, T c) {
  a = powmod(a, b, c);
}
int iszero(double a) { return abs(a) <= eps; }
template <class T>
void geti(T &a) {
  a = 0;
  int b = 1, c = getchar();
  if (c == '-')
    b = -1;
  else
    a = c - 48;
  while ((c = getchar()) != ' ' && c != '\n') a = a * 10 + c - 48;
  a *= b;
}
void fileio_in_out() {
  freopen(".in", "r", stdin);
  freopen(".out", "w", stdout);
}
void fileio_txt() {
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
}
const int N = 1111111;
int test;
long long n, m, k, ans;
map<pair<long long, long long>, pair<long long, long long> > Map;
pair<long long, long long> dfs(pair<long long, long long> p) {
  if (p.first == 0) return make_pair(0, 0);
  if (p.first < 10) return make_pair(1, p.second - p.first);
  if (Map.count(p)) return Map[p];
  pair<long long, long long> ret = make_pair(0, 0), tp = p;
  long long t = 1;
  while (t <= p.first / 10) t *= 10;
  while (1) {
    long long high = p.first / t, maxx = max(high, p.second);
    pair<long long, long long> next = dfs(make_pair(p.first % t, maxx));
    ret.first += next.first;
    p.first -= p.first % t;
    if (next.second > 0)
      p.first -= next.second;
    else {
      if (maxx > 0) {
        p.first -= maxx;
        ret.first++;
      }
    }
    if (high == 0) break;
  }
  ret.second = -p.first;
  Map[tp] = ret;
  return ret;
}
int main() {
  scanf("%I64d", &n);
  ans = dfs(make_pair(n, 0)).first;
  printf("%I64d\n", ans);
  return 0;
}
