https://www.acmicpc.net/problem/1110
import java.io.*;
class Main {
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
int N = Integer.parseInt(br.readLine());
int origin = N;
int cnt = 0;
while (true) {
N = (N / 10 + N % 10) % 10 + (N % 10) * 10;
cnt++;
if (N == origin) {
break;
}
}
System.out.println(cnt);
}
}