type vector=record
     x,y:integer;
     end;
var v:array[1..100] of vector;
    n,i,j,l,u,s1,s2:integer;
    q:real;
    f,g:text;
begin
assign(f,'secv3.in');
assign(g,'secv3.out');
reset(f);
rewrite(g);
readln(f,n,l,u);
for i:=1 to n do read(f,v[i].x);
readln(f);
for i:=1 to n do read(f,v[i].y);
for i:=1 to n do begin
    s1:=v[i].x;
    s2:=v[i].y;
    if (i>=l) and (s1/s2>q) then q:=s1/s2;
if i<n then for j:=i+1 to n do begin
        s1:=s1+v[j].x;
        s2:=s2+v[j].y;
        if (s1/s2>q) and (j-i+1>l) then q:=s1/s2;
        if (j-i+1=u) or (j=n) then j:=n;
        end;
end;
writeln(g,q:3:2);
close(f);
close(g);
end.