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++14 (GCC 5.4.1) (judge verdict: Accepted)

 #include<bits/stdc++.h>
#define D(x) cout<<"D: "<<#x<<'='<<x<<endl;
#define R(x, l) cout<<"R: Array "<<#x<<endl; for(int i = 0; i < l; i++) cout<<' '<<i<<':'<<*(x+i)<<endl;
#define pb push_back
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
template<typename tn> inline tn next(void)
{
	tn k;
	cin>>k;
	return k;
}
template<typename tn> inline ostream& operator << (ostream& os, const vector<tn>& v)
{
	for(unsigned i = 0; i < v.size(); i++) os<<v[i]<<' ';
	return os;
}
inline bool is_pa(string str)
{
	for(int i = 0; i < str.length()/2; i++)
		if (str[i] != str[str.length()-i-1]) return 0;
	return 1;
}
int main(void)
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	string s = next<string>();
	string str = " ";
	for(int i = 0; i < s.length(); i++) str.pb(s[i]);
	int l = s.length();
	string a = str.substr(1, (l-1)/2), b = str.substr((l+3)/2, l);
	if (is_pa(s) && is_pa(a) && is_pa(b)) puts("Yes");
	else puts("No");
	return ~~(0-0);
}