//gm --- akezhon
#include <bits/stdc++.h>
// #pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define pb push_back
#define pf push_front
#define F first
#define S second
#define all(v) v.begin(),v.end()
#define pii pair<int,int>
#define tm (tl+tr)/2
#define TL v+v, tl, tm
#define TR v+v+1, tm+1, tr
#define DA l <= tl && tr <= r
#define NE r < tl || tr < l
#define double long double
#define int long long
using namespace std;
const int N=3e5+7;
const int mod=1e9+7;
const int inf=2e18;
void AlemAmenov(){
int ans=0;
int n;
cin >> n;
vector<pii>v, v2;
for(int x, y, i=1; i <= n*2; i++){
cin >> x >> y;
if(y<=1){
ans+=1-y;
if(x < 1){
ans += 1-x;
v.pb({1, 1});
}
else if(n < x){
ans += x-n;
v.pb({n, 1});
}
else{
v.pb({x, 1});
}
}
else{
ans+=y-2;
if(x < 1){
ans += 1-x;
v.pb({1, 2});
}
else if(n < x){
ans += x-n;
v.pb({n, 2});
}
else{
v.pb({x, 2});
}
}
}
sort(all(v));
for(int i=0; i < n; i++){
if(v[i*2].F == v[i*2+1].F){
if(v[i*2].S == v[i*2+1].S){
int pos=0;
for(int j=i*2+2; j < v.size(); j++){
if(v[j].F != v[i*2].F)break;
if(v[j].S != v[i*2].S){
pos=j;
break;
}
}
if(!pos)ans++;
else{
swap(v[pos], v[i*2]);
}
}
}else if(v[i*2].S == v[i*2+1].S)ans++;
ans += abs(i+1 - v[i*2].F);
ans += abs(i+1 - v[i*2+1].F);
}
cout << ans;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int RealName=1;
// cin >> RealNam;
// srand(time(0));
while(RealName--)
AlemAmenov();
return 0;
}
