type matrice=array[1..20,1..20] of integer;
procedure citire(var a:matrice;var n,l,u:byte);
var f:text;
    i,j:integer;
begin
assign(f,'intrare.in');reset(f);
while not eof(f) do begin
read(f,n,l,u);
for i:=1 to 2 do
for j:=1 to  n do
read(f,a[i,j]);
end;
close(f);
end;
procedure afisare(a:matrice;n,l,u:byte);
var s,d,i,j,r:integer;
    h,max:real;
begin
max:=-maxint;s:=0;d:=0;h:=0;r:=0;
for i:=1 to 2 do begin
r:=0;s:=0;d:=0;
for j:=i to (i+u-1) do begin
inc(r);
inc(s,a[1,j]);
inc(d,a[2,j]);
if r>=l then begin
h:=s/d;
if h>max then max:=h;
end;
end;
end;
write(max);
end;
var a:matrice;
    n,l,u:byte;
begin
citire(a,n,l,u);
afisare(a,n,l,u);readln;end.