program criminalc;
var n,m,k,i,min,w:longword;
  l:longint;
  t:array[1..1000]of byte;
begin
  assign(input,'criminalc.in'); reset(input);
  assign(output,'criminalc.out'); rewrite(output);
  fillchar(t,sizeof(t),0);
  min:=0;
  readln(n,m,k);
  for i:=1 to m do begin read(w); t[w]:=1; end;
  for i:=1 to n do
  begin
    readln(l);
    if t[i]=1 then
    begin
      if l>0 then t[l]:=2 else t[-l]:=1;
    end
    else if t[i]=2 then begin
      if l>0 then t[l]:=1 else t[-l]:=2;
    end;
  end;
  min:=n-m;
  writeln(min);
  close(input); close(output);
end.