{$MODE OBJFPC}
const
  fi='';
  fo='';
  max=100010;
type
  diem=record
    x:longint;
    b:boolean;
end;
var
  f1,f2:text;
  F:array[0..2*max] of longint;
  res:longint;
  a:array[1..2*max] of diem;
  n:longint;
procedure input;
var
  i:longint;
begin
  Assign(f1,fi);reset(f1);
  readln(f1,n);
  For i:=1 to n do
  begin
    read(f1,a[i].x);
    a[i].b:=true;
  end;
  For i:=n+1 to 2*n do
    begin
      read(f1,a[i].x);
      a[i].b:=false;
    end;
  close(f1);
end;
procedure quicksort(l,r:longint);
var
  i,j,pivot:longint;
  temp:diem;
begin
  i:=l;
  j:=r;
  pivot:=a[random(r-l+1)+l].x;
  while i<=j do
    begin
      while a[i].x<pivot do inc(i);
      while a[j].x>pivot do dec(j);
      if i<=j then
        begin
          temp:=a[i];
          a[i]:=a[j];
          a[j]:=temp;
          inc(i);
          dec(j);
        end;
    end;
  if i<r then quicksort(i,r);
  if j>l then quicksort(l,j);
end;
function getmax(x,y:longint):longint;
begin
  if x<y then getmax:=y else
  getmax:=x;
end;
procedure slove;
var
  i,j:longint;
  t:longint;
begin
  Assign(f2,fo);rewrite(f2);
  quicksort(1,2*n);
  res:=0;
  F[0]:=0;
  if(a[1].b xor a[2].b=true) then F[1]:=1
  else F[1]:=0;
  For i:=2 to 2* n do
  begin
    F[i]:=F[i-1];
    if(a[i].b xor a[i-1].b=true) then F[i]:=getmax(F[i-2]+1,F[i-1])
  end;
  For i:=1 to 2*n do res:=getmax(res,F[i]);
  writeln(f2,res);
  close(f2);
end;
begin
  input;
  slove;
  //readln;
end.