uses crt;
var n,m,k,i:word;
begin
clrscr;
repeat
writeln('Vvedite natural'noe 4islo <9999');
readln(n);
until(n>0)and(n<9999);
for i:=9 downto 0 do
begin
m:=n;
while m>0 do
begin
k:=m mod 10;
if k=i then
begin
write(k);
break;
end
else m:=m div 10;
end;
end;
readln
end.