package algo;

import java.util.Scanner;

public class sample7 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String N = sc.next();
		char[] c = N.toCharArray();
		int cnt = 0;
		for(int i = 1; i < c.length; i++) {
			if(c[0] == '1' && c[i] == '3') {
				cnt++;
			}
			else {
				System.out.println(-1);
				return;
			}
		}
		System.out.println(cnt);
	}
}