// No.791 うし数列
package main

import (
	"fmt"
	"strings"
)

func main() {
	var n string
	fmt.Scan(&n)

	if strings.HasPrefix(n, "1") && len(n) > 1 {
		e := strings.Count(n, "3")
		if e == (len(n) - 1) {
			fmt.Println(e)
		} else {
			fmt.Println(-1)
		}
	} else {
		fmt.Println(-1)
	}
}