LargetCommonEnd

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

namespace LargestCommonEnd
{
    class LargeCommonEnd
    {
        static void Main()
        {
            string[] firstArr = Console.ReadLine().Split();
            string[] secondArr = Console.ReadLine().Split();
            int smallerArr = Math.Min(firstArr.Length, secondArr.Length);

            int leftCounter = CheckArrays(firstArr, secondArr, smallerArr);
            Array.Reverse(firstArr);
            Array.Reverse(secondArr);
            int rightCounter = CheckArrays(firstArr, secondArr, smallerArr);
            Console.WriteLine(Math.Max(leftCounter,rightCounter));
        }

        public static int CheckArrays(string[] firstArr, string[] secondArr, int smallerArr)
        {
            int counter = 0;
            for (int i = 0; i < smallerArr; i++)
            {
                if (firstArr[i] == secondArr[i])
                {
                    counter++;
                }
                else
                {
                    break;
                }
            }

            return counter;
        }
    }
}