1.Largest_Common_End

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

namespace _1.Largest_Common_End
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] array1 = Console.ReadLine().Split(' ');
            string[] array2 = Console.ReadLine().Split(' ');

            int largestArrayCount = array1.Length > array2.Length ? array1.Length : array2.Length;

            bool leftSideMatch = true;
            bool rightSideMatch = true;
            int leftCount = 0;
            int rightCount = 0;
            bool KeyExist = false;

            for (int i = 0; i < largestArrayCount; i++)
            {
                KeyExist = array1.Length > i && array2.Length > i ? true : false;
                if (KeyExist && (!string.IsNullOrEmpty(array1[i]) || !string.IsNullOrEmpty(array2[i])) && leftSideMatch)
                {
                    if (array1[i] == array2[i])
                    {
                        leftCount++;
                    }
                    else
                    {
                        leftSideMatch = false;
                    }
                }
                KeyExist = array1.Length > array1.Length - 1 - i && array2.Length > array2.Length - 1 - i ? true : false;
                if (KeyExist && (!string.IsNullOrEmpty(array1[array1.Length - 1 - i]) || !string.IsNullOrEmpty(array2[array2.Length - 1 - i])) && rightSideMatch)
                {
                    if (array1[array1.Length - 1 - i] == array2[array2.Length - 1 - i])
                    {
                        rightCount++;
                    }
                    else
                    {
                        rightSideMatch = false;
                    }
                }
                if (rightSideMatch == false && leftSideMatch == false)
                {
                    break;
                }
            }
            Console.WriteLine(leftCount > rightCount ? leftCount : rightCount);
        }
    }
}