using System;
namespace yukicoder
{
    class Program
    {

        static void Main(string[] args)
        {
            var str = Console.ReadLine();

            var str2 = Console.ReadLine();
            int temp = 0;
            string[] strings = new string[str.Length + str.Length];
            int vacation = 1, Maxvacation = 0;
            for(int i = 0; i < str.Length; i++)
            {
                strings[i] = str.Substring(i , 1);
                strings[i + 7] = str2.Substring(i, 1);
            }
            for (int j = 0; j < strings.Length - 1; j++)
            {
                if (strings[j] == "o" && strings[j + 1] == "o")
                {
                    vacation++;
                }
                
                
                else
                {
                    temp = vacation;
                    if(temp > Maxvacation)
                    {
                        Maxvacation = temp;
                    }                   
                    vacation = 1;
                }
            }
            if(str == "xxxxxxx" && str2 == "xxxxxxx")
            {
                Maxvacation = 0;
            }
            Console.WriteLine(Maxvacation);
        }
    }
}