#include<iostream>
using namespace std;

int main() {

	int temp, input, count, fNum, bNum;
	fNum = bNum = temp = input = count = 0;

	cin >> input;
	temp = input;

	while (temp != input || count == 0) {
		count++;
		fNum = temp / 10;
		bNum = temp % 10;
		temp = fNum + bNum;
		if (temp < 10)
			temp += bNum * 10;
		else
			temp = temp % 10 + bNum * 10;
	}
	cout << count << endl;

	return 0;
}