program secventa3;
var f,g:text;
    a,b:array[1..30000]of longint;
    max:real;
    n,i,l,u,s,s2,j:longint;
begin
assign(f,'secv3.in');
assign(g,'secv3.out');
reset(f);
rewrite(g);
read(f,n,l,u);
for i:=1 to n do read(f,a[i]);
for i:=1 to n do read(f,b[i]);
for i:=1 to n-l+1 do
  begin
    s:=0;
    s2:=0;
    for j:=i to i+l-1 do
      begin
        s:=s+a[j];
        s2:=s2+b[j];
      end;
    if (s/s2>max)then max:=s/s2;
    for j:=i+l to i+u-1 do
      begin
        s:=s+a[j];
        s2:=s2+b[j];
        if (s/s2>max)then max:=s/s2;
      end;
  end;
write(g,max:6:2);
close(f);
close(g);
end.