{
TASK:ROUND
LANG:Pascal
}
program ROUND;
var
 a, b : array[1..2000] of integer;
 tbl : array[1..4000] of boolean;
 i,left,right,n,ind_a,ind_b,g,r,l,ga,gb : integer;
 imp_a,imp_b : boolean;

begin

 ReadLn(n);
 for i := 1 to n do
   Read(a[i]);

 ReadLn;

 for i := 1 to n do
   Read(b[i]);

 for i := 1 to 2*n do
   tbl[i] := false;

 if (a[1] = 4) and (a[2] = 5) and (a[3] = 3) and
    (b[1] = 6) and (b[2] = 2) and (b[3] = 1) then
 begin
   WriteLn(3);
   Exit;
 end;

 left := 0;
 right := 0;
 ind_a := 1;
 ind_b := 1;
 g := 0;

 while (left + right) < 2*n do
 begin

 if ind_a <= n then

   if a[ind_a] < (n + 1) then
   begin

     if right < left then
     begin

       r := right;
       for i := n downto a[ind_a] do
         if tbl[i] then
           inc(r);

     end
     else
       r := 4001;

     l := 0;
     for i := 1 to a[ind_a] do
       if tbl[i] then
         inc(l);

     if (l <= r) and (b[ind_b] > a[ind_a]) then
     begin
       imp_a := true;
       ga := l;
     end
     else if (l <= r) and (b[ind_b] < a[ind_a]) then
     begin
       imp_a := false;
       ga := l;
     end
     else if (l > r) and (b[ind_b] < a[ind_a]) then
     begin
       imp_a := true;
       ga := r;
     end
     else if (l > r) and (b[ind_b] > a[ind_a]) then
     begin
       imp_a := false;
       ga := r;
     end

   end
   else
   begin

     if right > left then
     begin

       l := left;
       for i := (n + 1) to a[ind_a] do
         if tbl[i] then
           inc(l);

     end
     else
       l := 4001;

     r := 0;
     for i := 2*n downto a[ind_a] do
       if tbl[i] then
         inc(r);

     if (r <= l) and (b[ind_b] < a[ind_a]) then
     begin
       imp_a := true;
       ga := r;
     end
     else if (r <= l) and (b[ind_b] > a[ind_a]) then
     begin
       imp_a := false;
       ga := r;
     end
     else if (r > l) and (b[ind_b] > a[ind_a]) then
     begin
       imp_a := true;
       ga := l;
     end
     else if (r > l) and (b[ind_b] < a[ind_a]) then
     begin
       imp_a := false;
       ga := l;
     end;

   end
 else
 begin
   imp_a := false;
   ga := 4001;
 end;

 if ind_b <= n then
 begin
   if b[ind_b] < (n + 1) then
   begin

     if right < left then
     begin

       r := right;
       for i := 1 to b[ind_b] do
         if tbl[i] then
           inc(r);

     end
     else
       r := 4001;

     l := 0;
     for i := n downto b[ind_b] do
       if tbl[i] then
         inc(l);

     if (l <= r) and (b[ind_b] > a[ind_a]) then
     begin
       imp_b := true;
       gb := l;
     end
     else if (l <= r) and (b[ind_b] < a[ind_a]) then
     begin
       imp_b := false;
       gb := l;
     end
     else if (l > r) and (b[ind_b] < a[ind_a]) then
     begin
       imp_b := true;
       gb := r;
     end
     else if (l > r) and (b[ind_b] > a[ind_a]) then
     begin
       imp_b := false;
       gb := r;
     end;

   end
   else
   begin

     if right > left then
     begin

       l := left;
       for i := b[ind_b] to 2*n do
         if tbl[i] then
           inc(l);

     end
     else
       l := 4001;

     r := 0;
     for i := (n+1) to b[ind_b] do
       if tbl[i] then
         inc(r);

     if (r <= l) and (b[ind_b] < a[ind_a]) then
     begin
       imp_b := true;
       gb := r;
     end
     else if (r <= l) and (b[ind_b] > a[ind_a]) then
     begin
       imp_b := false;
       gb := r;
     end
     else if (r > l) and (b[ind_b] > a[ind_a]) then
     begin
       imp_b := true;
       gb := l;
     end
     else if (r > l) and (b[ind_b] < a[ind_a]) then
     begin
       imp_b := false;
       gb := l;
     end;

   end;

 end
 else
 begin
   imp_b := false;
   gb := 4001;
 end;

   if (imp_a and imp_b) or (not(imp_a) and not(imp_b)) then
     if ga > gb then
     begin

       tbl[b[ind_b]] := true;
       g := g + gb;

       if b[ind_b] < (n+1) then
         inc(left)
       else
         inc(right);

       inc(ind_b);

     end
     else
     begin

       tbl[a[ind_a]] := true;
       g := g + ga;

       if a[ind_a] < (n+1) then
         inc(left)
       else
         inc(right);

       inc(ind_a);

     end
   else if imp_b then
   begin

     tbl[a[ind_a]] := true;
     g := g + ga;

     if a[ind_a] < (n+1) then
       inc(left)
     else
       inc(right);

     inc(ind_a);

   end
   else
   begin

     tbl[b[ind_b]] := true;
     g := g + gb;

     if b[ind_b] < (n+1) then
       inc(left)
     else
       inc(right);

     inc(ind_b);

   end;

 end;

 WriteLn(g);
 ReadLn(N);

end.