#include <iostream> #include <vector> #include <string> #include <algorithm> #include <map> #include <set> #include <queue> #include <stack> #include <deque> #include <cmath> #include <climits> #include <cstring> #include <iomanip> #include <numeric> #include <functional> #include <bitset> #include <unordered_map> #include <unordered_set> #include <chrono> #include <random> using namespace std; typedef long long ll; typedef unsigned long long ull; typedef long double ld; #define rep(a,b) for(int a = 0;a<b;a++) #define st first #define nd second #define pb push_back #define all(a) a.begin(),a.end() const int inf = 1e9; const ll infl = 1e18; int tab[100007][2]; int main() { ios_base::sync_with_stdio(0); cin.tie(0); int n; cin >> n; ll w = 0; rep(i, 2*n){ ll a, b; cin >> a >> b; if(a >= 1 && a <= n){ //cout << "sigma " << a << " " << b << "\n"; if(b == 1 || b == 2){ tab[a-1][b%2]++; //cout << "sigma " << a << " " << b << "\n"; } else if(b < 1){ tab[a-1][1]++; w += -b+1; } else{ tab[a-1][0]++; w += b-2; } } else if(b == 1 || b == 2){ if(a > n){ tab[n-1][(b+1)%2]++; w += a-n; } else{ tab[0][b%2]++; w += -a+1; } } else{ if(a > n && b > 2){ tab[n-1][0]++; w += a-n + b-2; } else if(a > n && b < 1){ tab[n-1][1]++; w += a-n - b+1; } else if(a < 1 && b > 2){ tab[0][0]++; w += -a+1 + b-2; } else if(a < 1 && b < 1){ tab[0][1]++; w += -a+1 -b + 1; } } } rep(i, n-1){ if(tab[i][0] > 0 && tab[i][1] > 0){ w+=tab[i][0]-1; tab[i+1][0] += tab[i][0]-1; w+=tab[i][1]-1; tab[i+1][1] += tab[i][1]-1; } else if(tab[i][0] <= 0 && tab[i][1] <= 0){ ll ile = abs(tab[i][0]-1); tab[i+1][0] -= ile; w+=ile; ile = abs(tab[i][1]-1); tab[i+1][1] -= ile; w+=ile; } else if(tab[i][0] <= 0 && tab[i][1] > 0){ ll ile = min(tab[i][1] - 1, 1 + abs(tab[i][0])); tab[i][0] += ile; tab[i][1] -= ile; w += ile; if(tab[i][0] <= 0){ tab[i+1][0] -= abs(tab[i][0] - 1); w += abs(tab[i][0] - 1); } if(tab[i][1] > 1){ tab[i+1][1] += tab[i][1] - 1; w += tab[i][1] - 1; } } else if(tab[i][0] > 0 && tab[i][1] <= 0){ ll ile = min(tab[i][0] - 1, 1 + abs(tab[i][1])); tab[i][1] += ile; tab[i][0] -= ile; w += ile; if(tab[i][1] <= 0){ tab[i+1][1] -= abs(tab[i][1] - 1); w += abs(tab[i][1] - 1); } if(tab[i][0] > 1){ tab[i+1][0] += tab[i][0] - 1; w += tab[i][0] - 1; } } } ll a = tab[n-1][0]; ll b = tab[n-1][1]; if(a < b){ swap(a, b); } w += a-1; cout << w << "\n"; return 0; }