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# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;

namespace ForATCODER
{
    public class Program
    {
        public static void Main(string[] args)
        {
            String s = Console.ReadLine();
          //  long[] nm = s2larray(Console.ReadLine().Split(' '));
           // long n = nm[0]; long m = nm[1];

          for(int i = 0; i < (s.Length/2);i++)
            {
                if(s[i] != s[s.Length - i-1])
                {
                    RESULT("No");
                    return;
                }
            }
            String s_ = s.Substring(0,s.Length/2);
            for (int i = 0; i < s_.Length / 2; i++)
            {
                if (s_[i] != s_[s_.Length - i-1])
                {
                    RESULT("No");
                    return;
                }
            }
            s_ = s.Substring(((s.Length+3)/2) -1, s.Length-1-(((s.Length + 3) / 2) - 1-1));
            for (int i = 0; i < s_.Length / 2; i++)
            {
                if (s_[i] != s_[s_.Length - i-1])
                {
                    RESULT("No");
                    return;
                }
            }
            RESULT("Yes");



        }
    
    



    
      
      
        static int s2i(String s)
        {
            return Convert.ToInt32(s);
        }
        static long s2l(String s)
        {
            return Convert.ToInt64(s);
        }
        static void RESULT(double res)
        {
            Console.WriteLine(res);
        }
        static void RESULT(long res)
        {
            Console.WriteLine(res);
        }
        static void RESULT(ulong res)
        {
            Console.WriteLine(res);
        }
        static void RESULT(int res)
        {
            Console.WriteLine(res);
        }
        static void RESULT(String res)
        {
            Console.WriteLine(res);
        }
        static String[] ReadLineAll(int count)
        {
            String[] res = new String[count];
            for (int i = 0; i < count; i++)
            {
                res[i] = Console.ReadLine();
            }
            return res;
        }

        static int[] s2iarray(String[] src)
        {
            int len = src.Length;
            int[] res = new int[len];
            for (int i = 0; i < len; i++)
            {
                res[i] = Convert.ToInt32(src[i]);
            }
            return res;
        }
        static long[] s2larray(String[] src)
        {
            int len = src.Length;
            long[] res = new long[len];
            for (int i = 0; i < len; i++)
            {
                res[i] = Convert.ToInt64(src[i]);
            }
            return res;
        }
    }
}