#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
class CoinCollector {
private:
int N;
vector<vector<ll>> coins;
ll result;
ll processInitialPosition(ll x, ll y) {
ll moves = 0;
if (x < 1) {
moves += 1 - x;
x = 1;
}
else if (x > N) {
moves += x - N;
x = N;
}
if (y < 1) {
moves += 1 - y;
y = 1;
}
else if (y > 2) {
moves += y - 2;
y = 2;
}
coins[x][y-1]++;
return moves;
}
ll moveCoins() {
ll moves = 0;
int up = 0, down = 0;
for (int i = 1; i <= N; i++) {
up += coins[i][0];
down += coins[i][1];
if (up > i && down < i) {
ll transfer = min(up - i, i - down);
moves += transfer;
up -= transfer;
down += transfer;
}
else if (up < i && down > i) {
ll transfer = min(down - i, i - up);
moves += transfer;
up += transfer;
down -= transfer;
}
moves += abs(up - i);
moves += abs(down - i);
}
return moves;
}
public:
ll solve() {
cin >> N;
coins.resize(N + 1, vector<ll>(2, 0));
result = 0;
for (int i = 0; i < 2 * N; i++) {
ll x, y;
cin >> x >> y;
result += processInitialPosition(x, y);
}
result += moveCoins();
return result;
}
};
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
CoinCollector solver;
cout << solver.solve() << endl;
return 0;
}
