{N$+}
var a:array[1..1000]of extended;
    b:array[1..1000]of extended;
    l,m,n:extended;
    i,k:integer;
    f1,f2:text;
begin
    assign(f1,'input.txt');
    assign(f2,'output.txt');
    reset(f1); rewrite(f2);
    while not eof(f1) do begin
    read(f1,l);
    i:=i+1;
    a[i]:=l;
    end;
    for k:=1 to i do begin
    b[k]:=sqrt(a[k]);
    end;
    for k:=i downto 1 do
    writeln(f2,b[k]:0:4);
    close(f1); close(f2);
end.
I don't believe...That works right on my computer but WA1!!!

see faq
-don't use i/o files
-use seekeof for numbers
-arrays [1000] is not enough

Thank's a lot