var a,b:string;
    c,i:longint;
begin
read(a);
c:=length(a);
for i:=c downto 1 do
b:=b+a[i];
if a=b then write('yes')
       else write('no');
       end.
/**************************************************************
	Problem: 1647
	User: admin
	Language: Pascal
	Result: Wrong Answer
****************************************************************/