#include<iostream> using namespace std; int main(){ char a[10001],ab[10001]; int now,find1; gets(a); int l; if(l%2==1) { find1=l/2+1; int i=0; while(i!=find1) { if(a[find1-i-1]!=a[find1+i-1]) { cout<<"No"; return 0; } else i++; } cout<<"Yes"; } else { find1=l/2; int i=0; while(i!=find1) { if(a[find1-i-1]!=a[find1+i]) { cout<<"no"; return 0; } else i++; } cout<<"yes"; } return 0; }