import java.io.*;

public class Main {
public static void main(String[] args) throws IOException{
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

    int n =  Integer.parseInt(br.readLine());
    int sum =0;
    int leftN =0;
    int rightN =0;
    int result = n;
    int a =0;

    while(true) {
        leftN = result/10;
        rightN = result%10;
        sum = leftN + rightN;
        result = rightN*10 + sum%10;
        a++;

        if(n == result) {
            break;
        }
    }
    bw.write(a +"\n");
    bw.flush();
    }
}