var
f1,f2:text;
c:char;
temp:string;
{ôóíêöèÿ ïðîâåðêè}
function Proverka(s:string):boolean;
var
i,j,count:integer;
fl:boolean;
begin
fl:=true;
count:=0;
i:=1;
while (fl) and (i<=length(s)-1) do
begin
for j:=i+1 to length(s) do
if (s[j]=s[i]) and ((s[j]<>' ') or (s[i]<>' ')) then
inc(count);
if count<>0 then
fl:=false;
inc(i)
end;
Result:=fl
end;
{îñíîâíàÿ ïðîãðàììà}
begin
assign(f1,'input.txt');
assign(f2,'output.txt');
reset(f1);
rewrite(f2);
while not EOF(f1) do
begin
temp:='';
while not EOLn(f1) do
begin
read(f1,c);
if c<>' ' then
temp:=temp+c;
if (c=' ') or (EOLn(f1)) then
begin
if Proverka(temp) then
write(f2,temp,' ');
temp:=''
end;
end;
writeln(f2);
readln(f1)
end;
close(f1);
close(f2)
end.