#include <bits/stdc++.h>
#define all(x) (x).begin(),(x).end()
using namespace std;
using ll = long long;
using ld = long double;
#define int ll
#define sz(x) ((int)(x).size())
using pii = pair<int,int>;
using tii = tuple<int,int,int>;
const int nmax = 1e6 + 5;
int v[nmax][2];
signed main() {
cin.tie(0) -> sync_with_stdio(0);
int n;
cin >> n;
ll cost = 0;
for(int i = 1, x, y; i <= 2 * n; i++) {
cin >> x >> y;
cost += min(abs(y - 1), abs(y - 2));
if(x <= 1) cost += 1 - x, x = 1;
else if(x >= n) cost += x - n, x = n;
if(y <= 1) v[x][0]++;
else v[x][1]++;
}
int cnt[2] = {0, 0};
for(int i = 1; i <= n; i++) {
cnt[0] += v[i][0];
cnt[1] += v[i][1];
cnt[0]--;
cnt[1]--;
while(cnt[0] > 0 && cnt[1] < 0) cnt[0]--, cnt[1]++, cost++;
while(cnt[1] > 0 && cnt[0] < 0) cnt[1]--, cnt[0]++, cost++;
cost += abs(cnt[0]) + abs(cnt[1]);
}
cout << cost << '\n';
}
/**
nu mancati chipsuri
-- gen, pe bune, sa nu mancati chipsuri
-- surse foarte verificate
-- eu unul nu mai bag chipsuri inainte de concurs
*/
