var t,s,v:array[0..100000] of longint;
    f,g:text;
    n,k,a,b,i,tot:longint;
begin
 assign(f,'divk.in'); reset(f);
 assign(g,'divk.out'); rewrite(g);
 read(f,n,k,a,b);
 tot:=0;
 for i:=1 to n do begin
  read(f,t[i]);
  s[i]:=s[i-1]+1;
  if i>=b then
   dec(v[s[i-b+1] mod k]);
  if i>=a then
   inc(v[s[i-a+2] mod k]);
  tot:=tot+v[s[i] mod k];
 end;
 writeln(g,tot);
 close(f); close(g);
end.