#include <iostream>
#include <string>
using namespace std;

string f(string x) {
	int mult = 1;
	for (int i = 0; i < x.length(); i++) {
		mult *= int(x.at(i)) - int('0');
	}
	string result = to_string(mult);
	return result;
}

int main() {
	string inp;
	while (cin >> inp) {
		int count = 0;
		while (inp.length() > 1) {
			inp = f(inp);
			count++;
		}
		cout << count << endl;
	}
	return 0;
}