#include <bits/stdc++.h>
using namespace std;
#define int long long
mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());
void Solve()
{
int n;
cin >> n;
vector<vector<int> > cnt(n + 2, vector<int> (3, -1));
int ans = 0;
for(int i = 1; i <= n * 2; i++)
{
int x, y;
cin >> x >> y;
if(x <= 0)
{
ans += 1 - x;
x = 1;
}
if(x > n)
{
ans += x - n;
x = n;
}
if(y <= 0)
{
ans += 1 - y;
y = 1;
}
if(y > 2)
{
ans += y - 2;
y = 2;
}
cnt[x][y]++;
}
for(int i = 1; i <= n; i++)
{
if(cnt[i][1] < 0 && cnt[i][2] > 0)
{
int diff = min(-cnt[i][1], cnt[i][2]);
ans += diff;
cnt[i][1] += diff;
cnt[i][2] -= diff;
}
if(cnt[i][1] > 0 && cnt[i][2] < 0)
{
int diff = min(cnt[i][1], -cnt[i][2]);
ans += diff;
cnt[i][1] -= diff;
cnt[i][2] += diff;
}
ans += abs(cnt[i][1]) + abs(cnt[i][2]);
cnt[i + 1][1] += cnt[i][1];
cnt[i + 1][2] += cnt[i][2];
}
cout << ans << "\n";
}
int32_t main()
{
auto begin = std::chrono::high_resolution_clock::now();
ios_base::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
for(int i = 1; i <= t; i++)
{
//cout << "Case #" << i << ": ";
Solve();
}
auto end = std::chrono::high_resolution_clock::now();
auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n";
return 0;
}
