using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace yukicoderTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string str = Console.ReadLine();
            int cnt = 0;
            int max = -1;
            bool flg = true;
            for (int i = 0; i < str.Length - 1; i++)
            {
                if (str.Substring(i, 1) == 1.ToString())
                {
                    for (int j = i + 1; j < str.Length; j++)
                    {
                        if (str.Substring(j, 1) == 3.ToString())
                        {
                            cnt++;
                        }
                        else
                        {
                            flg = false;
                            break;
                        }
                        if(cnt>max)
                        {
                            max = cnt;
                        }
                    }

                }
            }
            if (flg != false)
            {
                Console.WriteLine(max);
            }
            else
            {
                Console.WriteLine("-1");
            }
        }
    }
}