var l,r,a,b,n,i,t,max:longint;
    s,q:array[0..500000]of longint;
begin
 readln(n,a,b);
 s[0]:=0;
 for i:=1 to n do begin
  read(t);
  s[i]:=s[i-1]+t;
 end;
 l:=0; r:=-1;
 max:=-maxlongint;
 for i:=a to n do begin
  if (l<=r)and(i-q[l]>b) then inc(l);
  while (l<=r)and(s[i-a]-s[q[r]]<=0) do dec(r);
  inc(r); q[r]:=i-a;
  if s[i]-s[q[l]]>max then max:=s[i]-s[q[l]];
 end;
 writeln(max);
 close(input);
 close(output);
end.