/THIDAU - Kế hoạch thi đấu

              Uses Crt,Math;
      Var n,k,i,j,kq:longint;
          a,b,f:array[-100..10000] of longint;
      Begin
          readln(n,k);
          for i:=1 to n do read(a[i]);
          for i:=1 to n do read(b[i]);
          f[1]:=b[1];
          kq:=-maxlongint;
          for i:=2 to n do
           begin
               f[i]:=b[i];
               for j:=1 to i-1 do
                begin
                    if (abs(a[j]-a[i])>=k) then
                     begin
                         f[i]:=max(f[i],f[j]+b[i]);
                     end;
                    kq:=max(kq,f[i]);
                end;
           end;
           writeln(kq);
           readln;
      End.