program vijos_1280;

var n:integer;

f:array[0..61,0..31,-100..100]of boolean;

a:array[0..100,0..100]of integer;

procedure init;

var i,j:longint;

begin

assign(input,'v_1280.in');reset(input);

readln(n);

for i:=1 to n*2-1 do

for j:=1 to n-abs(n-i) do

read(a);

close(input);

end;

procedure main;

var i,j,k,min:longint;

begin

f[2*n-1,1,a[2*n-1,1]]:=true;

for i:=2*n-2 downto n do

for j:=1 to n-abs(n-i) do

for k:=-50 to 50 do

begin

if f then

f[i,j,a+k]:=true;

if f then

f[i,j,k-a]:=true;

if f then

f[i,j,a+k]:=true;

if f then

f[i,j,k-a]:=true;

end;

for i:=n+1 downto 1 do

for j:=1 to n-abs(n-i) do

for k:=-50 to 50 do

begin

if f then

f[i,j,a+k]:=true;

if f then

f[i,j,k-a]:=true;

if f then

f[i,j,a+k]:=true;

if f then

f[i,j,k-a]:=true;

end;

min:=maxint;

for i:=-50 to 50 do

if (f[1,1,i])and(abs(i)