uses crt;
const fi='xau.txt'
var f1:text;
s:string;
i,d,kt:integer;
begin
clrscr;
assign(f1,fi); reset(f1);
readln(f1,s);
d:=length(s);
kt:=0;
for i:=1 to d do
if st[i]<>st[d-i+1] then kt:=1;
if kt=0 then writeln('Xau doi xung')
else writeln('Xau khong doi xung');
readln;
end.