Problem:
Score : 200 points

Problem Statement

A string S of an odd length is said to be a strong palindrome if and only if all of the following conditions are satisfied:

S is a palindrome.

Let N be the length of S. The string formed by the 1-st through ((N-1)/2)-th characters of S is a palindrome.

The string consisting of the (N+3)/2-st through N-th characters of S is a palindrome.

Determine whether S is a strong palindrome.

Constraints

S consists of lowercase English letters.

The length of S is an odd number between 3 and 99 (inclusive).

Input

Input is given from Standard Input in the following format:

S

Output

If S is a strong palindrome, print Yes;
otherwise, print No.

Sample Input 1

akasaka

Sample Output 1

Yes

S is akasaka.

The string formed by the 1-st through the 3-rd characters is aka.

The string formed by the 5-th through the 7-th characters is aka.
All of these are palindromes, so S is a strong palindrome.

Sample Input 2

level

Sample Output 2

No

Sample Input 3

atcoder

Sample Output 3

No

Solution in C# (.NET Core 3.1.201) (judge verdict: Accepted)

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

namespace Atc_0027
{
    class Program
    {
        static void Main(string[] args)
        {
            var str = Console.ReadLine();

            string revS = "";

            revS = Reverse(str);

            if (str != revS)
            {
                Console.WriteLine("No");
                return;
            }

            string Astr = str.Substring(0, (str.Length - 1) / 2);

            revS = Reverse(Astr);

            if (Astr != revS)
            {
                Console.WriteLine("No");
                return;
            }

            string Bstr = str.Substring((str.Length + 3) / 2 - 1, str.Length - (str.Length + 3) / 2 + 1);

            revS = Reverse(Bstr);

            if (Bstr != revS)
            {
                Console.WriteLine("No");

                return;
            }

            Console.WriteLine("Yes");

        }

        static string Reverse(string r)
        {
            string revS = "";

            for (int i = 0; i < r.Length; i++)
            {
                revS += r.Substring(r.Length - 1 - i, 1);
            }

            return revS;
        }
    }
}