#include<bits/stdc++.h>
typedef long long ll;
#define pb push_back
#define fr first
#define sc second
#define endl '\n'
using namespace std;
int n;
int arr[100023][2];
ll ans=0;
const bool boceksizlestir=false;
int main(){
ios_base::sync_with_stdio(23^23);cin.tie(NULL);
cin>>n;
for(int i=1;i<=2*n;i++){
pair<int,int>p;cin>>p.fr>>p.sc;
if(p.fr<1){
ans+=1-p.fr;
p.fr=1;
}
if(p.fr>n){
ans+=p.fr-n;
p.fr=n;
}
if(p.sc<1){
ans+=1-p.sc;
p.sc=1;
}
if(p.sc>2){
ans+=p.sc-2;
p.sc=2;
}
arr[p.fr][p.sc-1]++;
}
vector<int>need[2];
for(int i=1;i<=n;i++){
if(arr[i][0]+arr[i][1]<2){
if(!arr[i][0]){
need[0].pb(i);
}
if(!arr[i][1]){
need[1].pb(i);
}
}
else{
while(arr[i][0]>1&&need[0].size()){
ans+=i-need[0].back();
arr[need[0].back()][0]++;
need[0].pop_back();
arr[i][0]--;
}
while(arr[i][1]>1&&need[1].size()){
ans+=i-need[1].back();
arr[need[1].back()][1]++;
need[1].pop_back();
arr[i][1]--;
}
while(arr[i][0]>1&&need[1].size()){
ans+=i-need[1].back()+1;
arr[need[1].back()][1]++;
need[1].pop_back();
arr[i][0]--;
}
while(arr[i][1]>1&&need[0].size()){
ans+=i-need[0].back()+1;
arr[need[0].back()][0]++;
need[0].pop_back();
arr[i][1]--;
}
if(arr[i][0]==0&&arr[i][1]>1){
ans++;
arr[i][1]--;
arr[i][0]++;
}
else if(arr[i][1]==0&&arr[i][0]>1){
ans++;
arr[i][0]--;
arr[i][1]++;
}
int x=max(0,arr[i][0]-1);
ans+=x;
arr[i+1][0]+=x;
arr[i][0]-=x;
x=max(0,arr[i][1]-1);
ans+=x;
arr[i+1][1]+=x;
arr[i][1]-=x;
if(!arr[i][0]){
need[0].pb(i);
}
if(!arr[i][1]){
need[1].pb(i);
}
}
if(boceksizlestir){
cout<<ans<<endl;
for(int i=0;i<2;i++){
for(int j=1;j<=n;j++){
cout<<arr[j][i]<<" ";
}
cout<<endl;
}
cout<<endl;
}
}
cout<<ans<<endl;
}
