//  Removing Digits

#include<bits/stdc++.h>

using namespace std;

int dp[(int)1e6 + 1];


int solve(int n) {
    if (dp[n]) return dp[n];
    int count = INT_MAX;
    if (n == 0) return 0;
    for (int i = 1; i <= 10 * n; i*= 10) {
        int remove = (n / i) - (n / (10 * i)) * 10;
        if (!remove) continue;
        count = min(count, 1 + solve(n - remove));
    }
    dp[n] = count;
    return count;
}


int main() {
    int n; cin >> n;
    cout << solve(n) << endl;
    return 0;
}