#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e5 + 7;
int a[N][3];
signed main() {
#ifdef HOME
freopen("input.txt", "r", stdin);
#else
ios_base::sync_with_stdio(0); cin.tie(0);
#endif
int n;
cin >> n;
int ans = 0;
for (int i = 0; i < 2 * n; ++i) {
int 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;
}
++a[x][y];
}
for (int i = 1; i <= n; ++i) {
for (int j = 1; j <= 2; ++j) {
a[i][j] += a[i - 1][j] - 1;
}
if (a[i][1] > 0 && a[i][2] < 0) {
int t = min(abs(a[i][1]), abs(a[i][2]));
a[i][1] -= t; a[i][2] += t;
ans += t;
}
if (a[i][1] < 0 && a[i][2] > 0) {
int t = min(abs(a[i][1]), abs(a[i][2]));
a[i][1] += t; a[i][2] -= t;
ans += t;
}
ans += abs(a[i][1]) + abs(a[i][2]);
}
cout << ans << '\n';
}
