Largest Common End

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

namespace LargestCommonEnd
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] arr1 = Console.ReadLine().Split(new char[0], StringSplitOptions.RemoveEmptyEntries).ToArray();
            string[] arr2 = Console.ReadLine().Split(new char[0], StringSplitOptions.RemoveEmptyEntries).ToArray();
            int loop = Math.Min(arr1.Length, arr2.Length); // old  int loop = Math.Min(arr1.Length, arr2.Length) - 1;

            int left = 0; int right = 0;

            for (int i = 0; i < loop; i++)
            {
                if (arr1[i] == arr2[i])
                {
                    left++;
                }
                if (arr1[arr1.Length - i - 1] == arr2[arr2.Length - i - 1])
                {
                    right++;
                }
            }
            if (left + right !=0)
            {
                Console.WriteLine(Math.Max(left, right));
            }
            else
            {
                Console.WriteLine(0);
            }
         }
    }
}