#include <bits/stdc++.h>
#define respagold ios_base::sync_with_stdio(0), cin.tie(0);
#define ll long long
#define int long long
#define int2 __int128_t
#define FOR( i, x, n, d ) for( int i = x; i <= n; i += d )
#define FORR( i, x, n, d ) for( int i = x; i >= n; i -= d )
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x.size())
#define pb push_back
#define ins insert
#define lb lower_bound
#define ub upper_bound
#define pii pair <int, int>
#define mkp make_pair
using namespace std;
const int N = 1e6 + 123;
const int inf = 2e18;
const int MOD = 1e9 + 7;
const int MOD1 = 998244353;
const int P = 6547;
int a[N], b[N], c[N], n, m, x, y, z, w;
int mz[N], used[N][2], dolg1[N], dolg2[N];
mt19937 rng( chrono::steady_clock::now().time_since_epoch().count());
int rand( int l, int r )
{
uniform_int_distribution <int> uid( l, r );
return uid( rng );
}
void solve()
{
cin >> n;
int ans = 0;
set <int> st1, st2;
FOR( i, 1, n * 2, 1 )
{
cin >> x >> y;
if( x < 1 ) ans += 1 - x, x = 1;
if( x > n ) ans += x - n, x = n;
if( y < 1 ) ans += 1 - y, y = 1;
if( y > 2 ) ans += y - 2, y = 2;
used[x][y] ++;
}
FOR( i, 1, n, 1 )
{
if( used[i][1] > 1 ) st1.ins(i);
if( used[i][2] > 1 ) st2.ins(i);
if( used[i][1] == 0 ) dolg1[i] = 1;
if( used[i][2] == 0 ) dolg2[i] = 1;
used[i][1] --, used[i][2] --;
}
int sos1 = 0, sos2 = 0;
FOR( i, 1, n, 1 )
{
if( !dolg1[i] ) sos1 += used[i][1];
if( !dolg2[i] ) sos2 += used[i][2];
FORR( j, i - 1, 1, 1 )
{
sos1 -= dolg1[j];
sos2 -= dolg2[j];
}
if( sos1 < sos2 && sos2 > 0 && sos1 < 0 )
{
FORR( j, i - 1, 1, 1 )
{
sos1 += dolg1[j];
sos2 -= dolg1[j];
dolg1[j] = 0;
ans += i - j + 1;
if( sos2 == 0 ) break;
}
}
if( sos1 > sos2 && sos2 < 0 && sos1 > 0 )
{
FORR( j, i - 1, 1, 1 )
{
sos1 += dolg2[j];
sos2 -= dolg2[j];
dolg2[j] = 0;
ans += i - j + 1;
if( sos2 == 0 ) break;
}
}
FORR( j, i - 1, 1, 1 )
{
sos1 += dolg1[i];
sos2 += dolg2[i];
}
}
FOR( j, 1, n, 1 ) ans += dolg1[j] + dolg2[j];
cout << ans;
}
signed main()
{
// freopen("connect.in", "r", stdin);
// freopen("connect.out", "w", stdout);
respagold
int test = 1;
if( !test ) cin >> test;
while( test -- )
{
solve();
}
}
// solved by KluydQ
