#include <bits/stdc++.h>   using namespace std;   long long int maxd(long long int n) {     long long int temp = 10 * n, mm = 0;     while (temp /= 10) mm = max(mm, temp % 10);     return mm;   }   int main() {     long long int n, ans = 0;     cin >> n;     while (n) {       n -= maxd(n);       ans++;     }     cout << ans;     return 0;   }   