const f='divk.in';g='divk.out';
var
    n,k,a,b,i:longint;
    rez:longint;
    v,s,c:array[0..500001] of longint;
    buf:array[1..1 shl 20] of char;
    buf1:array[1..1 shl 15] of char;
begin
    assign(input,f);reset(input);
    assign(output,g);rewrite(output);
    settextbuf(output,buf1);
    settextbuf(input,buf);
    readln(n,k,a,b);
    for i:=1 to n do
        begin
        readln(v[i]);
        s[i]:=(s[i-1]+v[i])mod k;
        end;
    for i:=a to n do
        begin
        inc(c[s[i-a]]);
        if i>b then c[s[i-b-1]]:=c[s[i-b-1]]-1;
        rez:=rez + c[s[i]];
        end;
    write(rez);
    close(input);close(output);
end.