begin
while 5 < 10 do
begin
write ('m,i,s,d....');
readln (op);
case op of
'm' : ubsmakenull(u);
'i' : begin
write('character... ');
readln (i);
ubsinsert(i,u);
end;
's' : begin
write('character... ');
readln (i);
if ubssearch(i,r,u) then writeln(r) else writeln ('not');
end;
'd': ubsdump(u,output);
end;
end;
end.
