NGHICHDAO PASCAL

var a,s:real;
begin
    assign(input,'NGHICHDAO.inp');reset(input);
    assign(output,'NGHICHDAO.out');rewrite(output);
    read(a);
    if a=0 then 
        write('khong co');
    if a<>0 then
    begin
        s:=1/a;
        writeln(s:0:4);
    end;
end.