#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
ll c[200005][3];
int main()
{
int n;
cin>>n;
ll ans = 0;
for(int i=0;i<2*n;i++){
int x,y;
cin>>x>>y;
if(x<1){
ans+=1-x;
x = 1;
}else if(x>n){
ans+=x-n;
x = n;
}
if(y<1){
ans+=1-y;
y = 1;
}else if(y>2){
ans+=y-2;
y = 2;
}
c[x][y]++;
}
for(int i=1;i<=n;i++){
c[i][1]--;c[i][2]--;
if(c[i][1] > 0 && c[i][2] < 0){
int tmp = min(c[i][1],-c[i][2]);
ans+=tmp;
c[i][1]-=tmp;
c[i][2]+=tmp;
}else if(c[i][1] < 0 && c[i][2] > 0){
int tmp = min(-c[i][1],c[i][2]);
ans+=tmp;
c[i][1]+=tmp;
c[i][2]-=tmp;
}
ans+=abs(c[i][1]);
ans+=abs(c[i][2]);
c[i+1][1]+=c[i][1];
c[i+1][2]+=c[i][2];
}
cout<<ans<<'\n';
}
