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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
#include<string.h>
 int main(void)
 {
   char S[100];
   int N,j,c=0,i=0,k=0,l=0;
   scanf("%s",S);
   N=strlen(S)-1;
   k=(N-1)/2;
   l=(N+3)/2;
   for(j=0;j<=N;j++)
     if(S[j]==S[N-j]) c=1;
     else c=4;
   if(c==1){
     for(j=0;j<=k;j++)
       if(S[j]==S[k-j]) c=2;
       else c=4;
   }
   if(c==2){
     for(j=l;j<=N;j++)
       if(S[j]==S[N-i]) {i++; c=3;}
       else c=4;
   }
   
   if(c==3) printf("Yes\n");
   if(c==4) printf("No\n");
   return 0;
 }