// #pragma GCC target ("avx2")
// #pragma GCC optimization ("O3")
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
const int MOD = 1e9 + 7;
ll binpow(ll a, ll p, int mod = MOD) {
ll res = 1;
while (p) {
if (p & 1) {
(res *= a) %= mod;
}
p >>= 1;
(a *= a) %= mod;
}
return res;
}
ll gcd(ll a, ll b) {
return b == 0 ? a : gcd(b, a % b);
}
ll squeeze(ll& x, ll l, ll r) {
ll res = 0;
res += max(0LL, l - x);
res += max(0LL, x - r);
x = max(x, l);
x = min(x, r);
return res;
}
const int N = 2e5 + 2;
int cnt[N][2];
void solve() {
int n;
cin >> n;
ll ans = 0;
for (int i = 0; i < n * 2; i++) {
ll x, y;
cin >> x >> y;
x--, y--;
ans += squeeze(x, 0, n - 1);
ans += squeeze(y, 0, 1);
cnt[x][y]++;
}
for (int i = 0; i < n; i++) {
for (int j = 0; j < 2; j++) {
if (cnt[i][j] > 1) {
int delta = min(cnt[i][j] - 1, 1 - cnt[i][j ^ 1]);
delta = max(delta, 0);
ans += delta;
cnt[i][j] -= delta;
cnt[i][j ^ 1] += delta;
}
}
cnt[i + 1][0] += cnt[i][0] - 1;
cnt[i + 1][1] += cnt[i][1] - 1;
ans += abs(cnt[i][0] - 1);
ans += abs(cnt[i][1] - 1);
}
cout << ans << '\n';
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int T = 1;
// cin >> T;
for (int tc = 1; tc <= T; tc++) {
// cout << "Case #" << tc << ": ";
solve();
}
return 0;
}
