#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 1e5 + 5;
int dp[MAXN][3];
ll ans = 0;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n;
cin >> n;
for(int i = 1; i <= 2 * n; i++) {
ll x, y;
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;
}
dp[x][y]++;
}
ll carry1 = 0, carry2 = 0;
for(int i = 1; i <= n; i++) {
dp[i][1]--;
dp[i][2]--;
dp[i][1] += carry1;
dp[i][2] += carry2;
if(dp[i][1] > 0 && dp[i][2] < 0) {
int move = min(dp[i][1], -dp[i][2]);
ans += move;
dp[i][1] -= move;
dp[i][2] += move;
}
if(dp[i][2] > 0 && dp[i][1] < 0) {
int move = min(dp[i][2], -dp[i][1]);
ans += move;
dp[i][2] -= move;
dp[i][1] += move;
}
ans += abs(dp[i][1]) + abs(dp[i][2]);
carry1 = dp[i][1];
carry2 = dp[i][2];
}
cout << ans << "\n";
return 0;
}
