#include <iostream>
using namespace std;
int main() {
	string s1="",s2="",s;
	cin>>s;
	bool flag = false;

	for(int i=0;i<s.size()/2;i++){
		
		s1 += s[i];
	}
	for(int i=(s.size()+3)/2-1;i<s.size();i++){
		s2 += s[i];
	}
	//cout<<s1<<" "<<s2<<endl;
	if(s1 != s2)
		cout<<"No"<<endl;
	else
		cout<<"Yes"<<endl;
	return 0;
}