var f,g:text;
b:array[0..120000] of char;
a,c,t,p:array[0..30000] of longint;
ok:boolean;
n,l,u,j,i,k:longint;max:extended;
begin
assign(f,'secv3.in');
assign(g,'secv3.out');
reset(F);
rewrite(G);
readln(f,n,u,l);
n:=0;
readln(f,b);i:=0;b[0]:='0';
while b[i] in (['0'..'9']+[' ']) do
        begin
        inc(I);
        inc(n);
        a[n]:=0;
        while (b[i]in ['0'..'9']) do
                begin
                a[n]:=a[n]*10+ord(b[i])-48;
                inc(I);
                end;
        t[n]:=t[n-1]+a[n];
        end;
n:=0;
readln(f,b);i:=0;b[0]:='0';
while b[i] in (['0'..'9']+[' ']) do
        begin
        inc(I);
        inc(n);
        c[n]:=0;
        while (b[i]in ['0'..'9']) do
                begin
                c[n]:=c[n]*10+ord(b[i])-48;
                inc(I);
                end;
        p[n]:=p[n-1]+c[n];
        end;max:=0;
for i:=1 to n-u+1 do
for j:=i+u-1 to i+l-1 do
        if (p[j]-p[i-1])/(t[j]-t[i-1])>max then
                max:=(p[j]-p[i-1])/(t[j]-t[i-1]);
writeln(g,max:0:2);
close(F);
close(G);
end.