#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define st first
#define nd second
typedef long long ll;
typedef long double ld;
const ll I = 1'000'000'000'000'000'000LL;
const int II = 2'000'000'000;
const ll M = 1'000'000'007LL;
const int N = 1<<18;
pair<int, int> co[N];
int s[N][2];
ll D(int a)
{
if(a < 0) return -a;
return a;
}
void Solve()
{
int n;
ll answer = 0LL;
cin >> n;
for(int i = 1; i <= 2 * n; ++i)
{
cin >> co[i].st >> co[i].nd;
if(co[i].st < 1)
{answer += 1 - co[i].st; co[i].st = 1;}
if(co[i].st > n)
{answer += co[i].st - n; co[i].st = n;}
if(co[i].nd < 1)
{answer += 1 - co[i].nd; co[i].nd = 1;}
if(co[i].nd > 2)
{answer += co[i].nd - 2; co[i].nd = 2;}
// cout << "I: " << co[i].st << " " << co[i].nd << "\n";
++s[co[i].st][co[i].nd - 1];
}
//cout << answer << "\n";
for(int i = 1; i <= n; ++i)
{
//cout << "B: " << i << " " << s[i][0] << " " << s[i][1] << "\n";
int l = max(0, s[i][1] - 1);
l = min(l, max(0, 1 - s[i][0]));
s[i][0] += l; s[i][1] -= l;
answer += D(l);
l = max(0, s[i][0] - 1);
l = min(l, max(0, 1 - s[i][1]));
s[i][0] -= l; s[i][1] += l;
answer += D(l);
//cout << "E: " << i << " " << s[i][0] << " " << s[i][1] << "\n";
answer += D(s[i][0] - 1);
answer += D(s[i][1] - 1);
s[i + 1][0] += s[i][0] - 1;
s[i + 1][1] += s[i][1] - 1;
}
cout << answer << "\n";
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//int t; cin >> t;
//while(t--)
Solve();
return 0;
}
