
import java.util.*;
class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int N = sc.nextInt();
int T = N;
int count = 0;
while(true) {
int a = T / 10; // 첫번 째 추출
int b = T % 10; // 두번 째 추출
int c = (a + b) % 10;
T = (b*10) + c;
count++;
if(N == T) {
break;
}
}
System.out.print(count);
sc.close();
}
}