var d,d1:array[0..500001] of longint;
    i,j,a,b,k,n:longint;
    rs:qword;
    buf1:array[1..1 shl 17] of char;

begin
assign(input,'divk.in');
assign(output,'divk.out');
reset(input);
rewrite(output);
settextbuf(input,buf1);
 readln(n,k,a,b);
  for i:=1 to n do
   begin
    readln(d[i]);
    d[i]:=(d[i]+d[i-1]) mod k;
   end;

   for i:=a to n do
    begin
     inc(d1[d[i-a]]);
     if i>b then dec(d1[d[i-b-1]]);
     inc(rs,d1[d[i]]);
    end;

     writeln(rs);

close(input);
close(output);
{Totusi este trist in lume}
end.