import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
	static public void main(String[]args) throws Exception {
		Scanner sc = new Scanner(System.in);
		String n = sc.next();
		printAns(n);
	}

	static void printAns(String s) throws Exception {
		if( isValid(s) ) {
			int ans = s.length() -1;
			System.out.println(ans);
		} else {
			System.out.println(-1);
		}
	}

	static boolean isValid(String s) throws Exception {
		List<Character> list = new ArrayList<>();
		for(int i=0; i<s.length(); i++) {
			char c = s.charAt(i);
			if(c == '1' || c == '3') {
				//nothing
			} else {
				list.add(c);
			}
		}
		if(list.size() == 0) return true;
		return false;
	}
}