#include <bits/stdc++.h>
using namespace std;
#define int long long
int t, n, u, v, a[1000005], table[1000005][3], answer = 0, mod = 1e9 + 7;
string s;
mt19937_64 rng;
int mul(int x, int y){
if(y == 0) return 1;
int ans = mul(x, y / 2);
if(y % 2 == 0) return (ans * ans) % mod;
else return (((ans * ans) % mod) * x) % mod;
}
void solve(){
for(int i = 1; i <= n; i++){
for(int j = 1; j <= 2; j++) table[i][j]--;
}
for(int i = 1; i <= n; i++){
if(table[i - 1][1]) table[i][1] += table[i - 1][1];
if(table[i - 1][2]) table[i][2] += table[i - 1][2];
if(table[i][1] > 0 && table[i][2] < 0){
int num = min(abs(table[i][1]), abs(table[i][2]));
answer += num;
table[i][1] -= num;
table[i][2] += num;
}
else if(table[i][1] < 0 && table[i][2] > 0){
int num = min(abs(table[i][1]), abs(table[i][2]));
answer += num;
table[i][1] += num;
table[i][2] -= num;
}
answer += abs(table[i][1]) + abs(table[i][2]);
}
cout << answer;
}
signed main(){
ios_base::sync_with_stdio(NULL); cin.tie(nullptr); cout.tie(nullptr);
rng.seed((int)main ^ time(0));
#ifdef Kawaii
auto starttime = chrono::high_resolution_clock::now();
#endif
cin >> n;
for(int i = 1; i <= n + n; i++){
cin >> u >> v;
if(1 <= u && u <= n && 1 <= v && v <= 2) table[u][v]++;
else{
if(1 <= u && u <= n){
if(v > 2) table[u][2]++, answer += abs(v - 2);
else table[u][1]++, answer += abs(v - 1);
}
else if(1 <= v && v <= 2){
if(u > n) table[n][v]++, answer += abs(u - n);
else table[1][v]++, answer += abs(u - 1);
}
else{
int ans = abs(1 - u) + abs(1 - v);
ans = min(ans, abs(n - u) + abs(1 - v));
ans = min(ans, abs(1 - u) + abs(2 - v));
ans = min(ans, abs(n - u) + abs(2 - v));
if(ans == abs(1 - u) + abs(1 - v)) table[1][1]++;
else if(ans == abs(n - u) + abs(1 - v)) table[n][1]++;
else if(ans == abs(1 - u) + abs(2 - v)) table[1][2]++;
else table[n][2]++;
answer += ans;
}
}
}
solve();
#ifdef Kawaii
auto endtime = chrono::high_resolution_clock::now();
auto duration = chrono::duration_cast<chrono::milliseconds>(endtime - starttime).count();
cout << "\n=====" << "\nUsed: " << duration << " ms\n";
#endif
}
